Egg Consumption Patterns and Sustainability: Insights from the Portuguese Context

Abstract

Although consumption is a key engine of economic growth, it is also one of the main drivers of environmental degradation. In this context, a deeper understanding of consumers’ perceptions and behavior regarding sustainable products is essential for promoting a more sustainable future, with behavioral change being crucial to achieving it. This research study explores consumer behavior regarding sustainable egg consumption, a sector where production is frequently associated with environmental and ethical concerns such as animal welfare and intensive resource use. Based on a sample of 197 valid responses from Portuguese egg consumers collected through an online survey distributed between 27 February and 17 March, of the year 2025, and applying the Theory of Planned Behavior (TPB) framework through a structural equation modeling (SEM) approach, this study finds that consumers’ intention to consume sustainable eggs is influenced by their attitudes and subjective norms. Furthermore, actual consumption behavior is driven by both the intention to consume sustainable eggs and perceived behavioral control. By providing an in-depth analysis of consumer behavior related to sustainable egg consumption, this study contributes to the advancement of the scientific literature on the subject. It also aims to support policymakers and other stakeholders in designing and implementing more effective strategies to promote environmentally responsible consumption practices.

1. Introduction

The unprecedented increase in resource consumption over recent decades has firmly established environmental protection as a current critical global imperative [1]. The growing concern about the depletion of natural resources and the high levels of waste generation caused by an intensive economic growth have drawn the attention of governments and society to the urgent need to promote sustainable consumption [2]. The unsustainable exploitation of natural resources has caused and exacerbated many environmental problems, such as the loss of biodiversity and increased pollution, threatening human well-being [3]. Although consumers are not solely responsible for this crisis, there is a growing consensus that unsustainable consumption patterns play a central role in driving the current environmental emergency [4].

In addition to greenhouse gas (GHG) emissions, the growth of intensive and industrialized agricultural production has been responsible for numerous environmental problems [5,6]. According to Sandström et al. [7], more than 80% of the GHG emissions of the European Union (EU) diets stem from the consumption of meat, dairy, and eggs. In the particular case of Portugal, national studies report that food consumption accounts for approximately 30% to the country’s ecological footprint [8]. Furthermore, the Portuguese population consumes more than three times the recommended amounts of meat, seafood, and eggs outlined in the National Food Wheel. Conversely, the consumption of fruits and vegetables remains significantly below the recommended levels [9]. These unsustainable dietary patterns have raised awareness among both consumers and companies about the urgent need to shift towards more sustainable consumption and production practices. While current consumption behaviors remain largely unsustainable, a growing interest in ecological products suggests an emerging shift in consumer awareness and a gradual move toward more environmentally friendly consumption practices [10]. There is still, however, a lack of strong political commitment in Portugal to promote dietary change, as highlighted by Galli et al. [8]. The effectiveness of measures such as product reformulation, already implemented in Portugal, largely depends on consumers’ habits and behaviors, particularly their willingness to seek out information. Without this engagement, such policies may prove effective in theory but inefficient in practice [11].

With the increase in awareness about the sustainability and environmental impact of food choices, products such as eggs, which offer an affordable and low-impact source of nutrition, have gained prominence in consumer preferences [12]. Eggs play a relevant role, as they are an economical food source of high biological value, capable of meeting the daily need for animal protein in an affordable way and with less environmental impact [13]. In addition, as awareness of animal welfare and environmental issues grows, consumers have shown a growing preference for eggs from cage-free farming systems, reflecting a shift in their dietary priorities [14]. In this context, the main objective of this study is to analyze the influence of attitudes, subjective norms, perceived behavioral control, and environmental awareness and concern on the intention and behavior of Portuguese consumers regarding organic and free-range egg consumption, using the Theory of Planned Behavior (TPB). It is important to note that in this study, organic and free-range eggs are treated as two distinct—though closely related—forms of sustainable egg production. Despite differences in production practices and regulatory frameworks, both contribute to improved animal welfare and environmental protection.

This research paper makes several important contributions to the scientific literature on sustainable food consumption, with a particular emphasis on sustainable egg consumption. It extends the TPB by integrating environmental awareness and concern as additional constructs alongside the traditional TPB variables, offering new insights into this research area. Moreover, the study focuses on the Portuguese market, where empirical and scientific studies on the consumption of organic and free-range eggs remain particularly scarce. These contributions aim to help bridge existing gaps in the literature while offering practical recommendations for policymakers and stakeholders in the food sector.

The paper is structured as follows: after the introduction, Section 2 reviews the scientific literature, exploring the main concepts related to sustainability in egg consumption. Section 3 describes the methodology adopted, including the questionnaire design, data collection, and sample profile. The results are then presented and discussed. Finally, Section 7 outlines the main conclusions, highlights the study’s limitations, and suggests potential avenues for future research.

2. Literature Review

2.1. Sustainability and Consumer Behavior

Consumer interest in eco-friendly products has grown significantly in recent years, with a notable global increase [1]. Both large and small companies are adapting their manufacturing processes to meet this demand, driven not only by regulatory requirements but also by evolving market needs [15]. In this context, consumers play a key role in driving the transition toward more sustainable production and consumption practices [2].

Studies indicate that the global market for eco-friendly products is valued at approximately EUR 44 trillion, representing more than half of the global Gross Domestic Product (GDP) [16]. Additionally, the low-carbon environmental goods and services market is valued at approximately at EUR 4.2 trillion, while the green technologies and sustainability sector was valued at EUR 11.49 billion in 2021. This growth has been further accelerated by the COVID-19 pandemic, which heightened public awareness of hygiene and well-being, leading to increased demand for products that are not only safe for families but also environmentally responsible [1]. These figures reflect a significant shift in consumer behavior, with consumption choices increasingly guided by attitudes and social norms that favor sustainability and environmental responsibility.

According to the Theory of Planned Behavior (TPB), consumer intentions and behaviors are shaped not only by individual attitudes and perceived behavioral control, but also by subjective norms [2,17,18]. This theoretical framework highlights the pivotal role of societal influence and social norms in shaping consumption patterns, particularly in the current context of increasing interest in eco-friendly products and a broader willingness to adopt sustainable behaviors.

A compelling illustration of this dynamic is found in the case of eggs, a staple food increasingly associated with debates on animal welfare and sustainability. The European civic initiative End the Cage Age, launched in 2018, sought to end the confinement of farm animals—especially laying hens—in cages [19]. Supported by around 1.5 million signatures, it was submitted to the European Commission, which pledged to assess its regulatory implications. In response, several major retailers announced plans to stop selling eggs from cage farming systems by 2025, a move expected to significantly affect the egg industry in EU Member States where such practices are still widespread. Cage farming has long sparked debate among animal welfare advocates, scientists, and producers, highlighting how shifting societal values and policy developments influence both production and consumer behavior [20]. This initiative exemplifies how public awareness, coupled with legislative pressure, can drive major transformations in the food sector. As a result, egg production is expected to continue its shift toward more humane and sustainable systems, shaped by market demand and regulatory change [21].

2.2. Consumer Perceptions and Preferences Regarding Regulations

The growing concern for sustainability and animal welfare has significantly influenced consumer perceptions and choices [22]. Regulations that impose higher standards on food production not only encourage more sustainable farming practices but also shape how consumers evaluate and choose products available on the market [23].

In Portugal, a study conducted by Euroconsumers [24] revealed that 55% of consumers consider animal welfare a highly important factor in their purchasing decisions. Among the products evaluated, eggs were identified as the most affected by this concern, influencing the choices of approximately 33% of respondents, followed by milk and dairy products (30%) and fresh poultry meat (27%). These findings suggest that as consumer awareness of farming regulations and production practices grows, there is an increasing preference for products associated with higher ethical standards, such as eggs from cage-free or organic systems. Furthermore, 61% of respondents expressed support for the introduction of new legislation to ensure the welfare of farm animals, reflecting a rising demand for stricter regulation in the agri-food sector. However, the study also revealed that 72% of Portuguese consumers feel poorly or insufficiently informed about current legislation, underscoring the need for greater transparency and more effective communication from both regulatory authorities and food industry brands.

2.3. Industry and Innovation Challenges

Garcia [25] describes the egg industry as a complex and dynamic sector that currently faces multiple challenges, including growing concerns over animal welfare, environmental sustainability, and increasing market pressures.

Animal products accounted for 16% of global agri-food trade in 2018, with the EU emerging as the largest exporter (21%) and the fourth-largest importer (6%) [26]. According to van Zanten et al. [27], a fundamental redesign of the European food system could yield substantial environmental benefits both within Europe and globally. Their estimates suggest that a shift toward a self-sufficient, circular food system could reduce agricultural land use by up to 71% and cut greenhouse gas emissions per capita in agriculture by 29%, while still supporting the production of healthy food.

Consumer demand for higher animal welfare standards has also prompted a transition away from conventional cage systems toward cage-free alternatives, such as ground-based or free-range systems [28]. Outdoor access allows laying hens to express natural behaviors, including foraging and exploration. However, as Garcia [25] notes, these systems are associated with increased production costs, greater exposure to disease, and additional environmental risks. Producers are thus confronted with a more demanding market, where meeting the rising demand for organic and free-range eggs necessitates higher input costs, ultimately leading to elevated retail prices.

To remain competitive and aligned with shifting consumer expectations, the egg industry must adopt more efficient and ethically responsible management practices. This includes leveraging innovations in genetics, technology, and system design to enhance productivity, reduce environmental impact, and improve animal welfare outcomes [25].

2.4. Egg Consumer Behavior

Eggs are a staple in the diet of many Europeans, and numerous studies have examined consumer behavior related to this food product. According to Camilleri [2], these studies often draw on psychological and social frameworks, such as the Theory of Planned Behavior and the Value–Belief–Norm Theory. Their findings consistently indicate a gap between consumers’ stated environmental awareness and intentions to purchase sustainable products and their actual purchasing behavior. While many consumers claim a willingness to change habits and pay higher prices for sustainable options, market shares for these products remain relatively low.

De Marchi et al. [29] emphasize the role of environmental knowledge in shaping consumer preferences for sustainably produced foods. Their research on Italian consumers shows a strong valuation of sustainable egg attributes, particularly free-range farming, local sourcing, and biodiversity protection. Notably, environmental knowledge increases consumers’ willingness to pay (wtp) for these attributes. However, biodiversity protection is a less familiar concept for many, and its value is primarily recognized by those with higher levels of environmental awareness. Hartmann et al. [30] similarly found that limited consumer understanding of food’s environmental impact hampers the effectiveness of public policy measures aimed at promoting sustainable consumption.

Rahmani et al. [31] investigated how Spanish consumers interpret egg types as indicators of animal welfare and environmental impact. Their findings revealed a low preference for organic eggs at actual market prices, suggesting a reluctance to pay the premium associated with this category. The study also identified a potential market segment for free-range eggs, characterized by younger consumers (under 40), with pro-environmental attitudes and monthly incomes exceeding EUR 1500, highlighting the influence of sociodemographic and economic factors on egg consumption behavior.

Wojciechowska-Solis and Barska [32] established a significant relationship between environmental awareness and the propensity to purchase organic products, including eggs, among Polish consumers. Key motivations for buying organic items included perceived health benefits, superior nutritional content, and the absence of additives in food production.

In the Netherlands, de Olde et al. [33] examined sustainability challenges within the egg sector through interviews with 24 stakeholders. They found that consumer interest primarily centers on animal welfare and efficient resource use (e.g., soil, energy, nutrients, and feed). A circular agricultural model—emphasizing regional integration of feed and manure cycles—was proposed by several stakeholders as a solution to nutrient surpluses and organic waste. The authors argue that stakeholder collaboration and consensus-building are essential to advancing sustainable egg production.

A study focusing on Norwegian consumers [34] found that wtp for organic eggs is higher among those who regularly purchase organic food. Nonetheless, a portion of consumers remain unwilling to buy organic eggs, even when priced equivalently to conventional options.

In Türkiye, Güney and Giraldo [35] found that consumers perceive organic eggs as healthier, more nutritious, and tastier. However, the decision to purchase these eggs is primarily driven by perceived personal benefits rather than collective or environmental concerns.

Pettersson et al. [36] observed that British consumers associate free-range eggs with better taste and perceive the hens as “happier” and “healthier”. While opinions varied on the factors contributing to chicken welfare, there was broad agreement on the importance of adequate resources.

In Portugal, a study [37] identified the primary concerns of egg consumers as the expiration date (92.6%), the absence of cracks (89.5%), and cleanliness (86.1%), all indicators of quality and safety. Other influential factors include price (67.7%), country of origin (65.3%), and production method (51.5%), the latter of which affects consumer perceptions of health and safety. Nutritional value (34.1%) and brand (22.6%) were found to have less influence on purchasing decisions.

3. Theoretical Framework and Research Hypotheses

3.1. Theory of Planned Behavior

This study seeks to explore the impact of various factors on individuals’ consumption intentions and behaviors concerning eggs produced through more sustainable methods and practices. Thus, the methodology used to explain and predict human behavior was the Theory of Planned Behavior (TPB) [17,38], which is based on Fishbein and Ajzen’s [39] Theory of Reasoned Action (TRA). In addition to providing an accessible and empirically supported conceptual framework, TPB has well-established guidelines for the measurement of its sociopsychological constructs [38]. The TPB posits that individuals’ attitudes, subjective norms, and perceived behavioral control are key factors that influence their intention to perform a specific behavior. This theory builds on the earlier TRA, which suggests that an individual’s actual behavior is directed by their intention to engage in that behavior.

The TPB has been implemented globally to investigate individuals’ consumption behaviors concerning various products and services. This approach has also frequently been particularly instrumental in understanding the underlying motivations behind pro-environmental behaviors [40]. Nevertheless, as illustrated in

Table 1. Studies focusing on consumer’s behavior regarding eggs and sustainability.

Authors	Country	Methodology	Main Conclusions
De Marchi et al. [29]	Italy	Online survey 1013 respondents	Environmental knowledge influences the choice of sustainable eggs. Consumers value free-range farming, local production and the protection of biodiversity, but the latter is less recognized.
Hartmann et al. [30]	Switzerland	Online survey 612 respondents	Insufficient knowledge about the environmental impact of food makes it difficult to understand and make policies for sustainable consumption effective.
Rahmani et al. [31]	Spain	Discrete choice experiment 1045 respondents	Consumers are not willing to pay for organic eggs. Those who prefer free-range eggs are pro-environment, under 40 years old and earn more than EUR 1500 a month.
Wojciechowska-Solis & Barska [32]	Poland	Proprietary survey questionnaire 1067 respondents	There is a statistical link between the environmental awareness of consumers, which includes beneficial effects on health, nutritional content and the non-addition of substances in food production, and the tendency to buy organic products, such as eggs.
de Olde et al. [33]	Netherlands	Interviews & survey 24 stakeholders	The interest of consumers has focused predominantly on animal welfare and the efficient use of resources.
Gerini et al. [34]	Norway	Choice experiment 900 respondents	Consumers are more willing to pay for organic eggs when they buy organic food more often. However, a segment of consumers is not willing to buy organic eggs even if they cost the same as other eggs.
Güney & Giraldo [35]	Turkey	Choice experiment 552 respondents	Consumers have realized that organic eggs are healthy, nutritious, and delicious. In the consumer’s decision to buy organic eggs, individual benefits prevailed over collective benefits.
Pettersson et al. [36]	United Kingdom	Questionnaire 6378 respondents	Consumers perceive free-range eggs as having a better flavor and hens as being “happier” and “healthier”. Opinions differed on the factors that contribute to hen welfare, while they converged on the adequacy of resources.
Junqueira et al. [37]	Portugal	Online survey 933 respondents	Consumers are concerned about the quality and safety of eggs, price, origin, and production method. The criteria that have the least impact on the purchasing decision are the nutritional properties and the brand.

Source: Authors’ own elaboration.

, this methodology has been employed in only a small number of studies conducted within the past decade to investigate the sustainable attributes of eggs.

To investigate sustainable egg consumption behavior, this study implemented an extended TPB model (Figure 1). The research hypotheses, built through the TPB as well as previous literature in the area of food consumption assume that individual attitudes, subjective social norms and the perception of behavior control influence consumption intentions and the real behavior of the consumer.

After an exhaustive review of the literature and previous scientific studies, it was found that there was a need to extend the theory by including environmental awareness as an additional variable (Figure 1). The TPB, as originally formulated by Ajzen [38], postulates that behavioral intention is driven by attitude, subjective norms, and perceived behavioral control. However, when applied to sustainability-related behaviors, such as the consumption of sustainable products, these concepts may not fully capture the cognitive and informational factors that influence decision-making [41,42]. Environmental awareness plays a critical role in shaping more favorable attitudes toward sustainable consumption, strengthening social norms around green choices, and increasing individuals’ perceived ability to act responsibly [43]. Empirical studies have shown that greater environmental awareness is positively associated with green purchasing intentions and behaviors [44,45], suggesting its relevance in predicting sustainable consumption. Incorporating this variable into the conceptual model improves the explanatory power of the TPB, creating a more comprehensive and contextual model that captures the cognitive factors influencing consumers’ intentions to consume sustainable products.

3.2. Research Hypotheses

Attitude plays a significant role in predicting individual environmental behavior across various circumstances [38]. It represents the individual’s propensity to engage in a certain behavior, which is generated by a set of beliefs, perceptions, and knowledge [2]. Specifically, attitude considers whether the individual perceives the behavior as beneficial or harmful, favorable or unfavorable, thus shaping their intention to act [46]. Attitude has been considered in many studies as a strong predictor of intention to consume organic food (e.g., [47]). Generally, consumers possess positive beliefs about organic and free-range eggs, perceiving these products as safer, healthier, more nutritious, and of superior quality compared to conventional eggs. Several studies have highlighted the significant impact of consumer attitudes on their consumption intentions, revealing various facets of these attitudes. For example, Harper and Makatouni [48] emphasize the importance of ethical concerns and animal welfare, while Güney and Giraldo [35] focus more on individual benefits and perceptions of health and nutrition. Additionally, many consumers associate free-range eggs with a rejection of “industrialized” foods, indicating a preference for products that align with their values. This suggests that consumer attitudes towards organic and free-range eggs are multifaceted, encompassing ethical considerations and personal health beliefs. Regardless, attitudes shape the intention to act. Considering this reasoning, the following hypothesis is proposed:

Hypothesis 1 (H1):

Attitudes toward organic and free-range eggs positively influence the intention to consume organic or free-range eggs.

Subjective norms are a person’s perception of the societal pressures to either follow or deviate from specific behaviors. They capture a person’s view of what other people think and expect of them in terms of behavior [38]. Strong subjective norms can motivate individuals to align their behavior with the expectations of those around them. When making judgements about egg consumption decisions, consumers may be influenced by the opinions of friends, family, or peers. Numerous studies investigating organic food indicate that subjective norms play a significant role in influencing the intention to purchase organic products [49,50,51]. However, some inconsistencies have been observed in this relationship (e.g., [52]) which may vary depending on specific contexts, cultural factors, and the nature of the product. In the case of organic and free-range eggs, this relationship is particularly pertinent. These types of eggs are often associated with ethical consumption, animal welfare, and environmental sustainability, values that are increasingly supported by society. As noted by the European Commission [20], social norms that advocate for sustainability, such as a commitment to eco-friendly agricultural practices and the ethical treatment of animals, can positively influence consumers’ intentions to select organic and free-range eggs. This suggests that the rising social endorsement of these values may significantly impact consumer intention. Hence, this research paper proposes to explore:

Hypothesis 2 (H2):

Individuals’ subjective norms positively influence the intention to consume organic or free-range eggs.

Perceived behavioral control is basically how much control someone feels they have over a behavior. It depends on whether they think the behavior is easy or difficult to do [38]. It includes perceptions of internal factors, such as personal skills and confidence, as well as external factors, such as resources and obstacles that may facilitate or hinder the behavior’s execution. A higher level of perceived behavioral control often correlates with stronger intentions to act. Perceived behavioral control generally has a positive influence on the intention to consume organic food [51,53], which can be extended to organic and free-range eggs. Accessibility to eggs with more sustainable attributes and knowledge about the benefits of these attributes, among other perceived obstacles or facilitators, can impact the consumer’s perceived control when consuming eggs. Based on the aforementioned, the following hypothesis is proposed:

Hypothesis 3 (H3):

Perceived behavioral control positively influences the intention to consume organic or free-range eggs.

The TPB suggests that perceived behavioral control is also a direct determinant of behavior [38]. This means that when individuals perceive a high degree of control over a behavior, they are more likely to carry it out, regardless of their initial intentions. Such direct influence is particularly evident in contexts where actual behavioral control closely aligns with perceived control, making perceived behavioral control a strong predictor of both intention and action. On this basis, the following hypothesis is proposed:

Hypothesis 4 (H4):

Perceived behavioral control positively influences the consumption behavior of organic or free-range eggs.

As individuals develop heightened awareness and concern regarding critical environmental issues—such as climate change, biodiversity loss, and the need for sustainable agriculture—they are increasingly likely to engage in more responsible consumption behaviors. They therefore seek products that not only meet their needs but are also aligned with their values and ethical standards [40,54]. This relationship between environmental concern and consumer intention has been substantiated by previous studies [49,54,55], highlighting the intrinsic connection between a person’s ecological awareness and their preference for organic products. Thus, it should be considered that more environmentally conscious and concerned individuals tend to view the consumption of organic/egg-range eggs products positively and feel motivated by social expectations, increasing their intention to adopt this behavior [14]. Therefore, another research hypothesis of this research paper is as follows:

Hypothesis 5 (H5):

Environmental awareness and concern positively influence the intention to consume organic or free-range eggs.

According to the TPB, intention denotes an individual’s inclination to engage in a specific behavior. It represents a consumer’s motivation and commitment to carry out a behavior and acts as a mediator between attitude, subjective norm, and perceived behavioral control. The individual’s intention to act has a high correlation with behavior. An individual is more likely to engage in a specific behavior if their intention is greater [38]. Several studies support the positive relationship between intention and behavior in sustainable food consumption. For instance, Akbar et al. [56] indicates that the intention to purchase is positively associated with consumer buying behavior regarding organic food, as demonstrated in their study of university students in Pakistan. Similarly, Ferreira and Pereira [57] found, for organic food, a significant positive relationship between purchase intention and purchase behavior in their research conducted in Portugal. Nonetheless, this relationship is not universally consistent. For example, a study focusing on Chinese university students, [58] identified an intention–behavior gap in the consumption of organic food. This disparity underscores the importance of further exploring the relationship between intention and behavior, particularly in the context of organic and free-range eggs. Therefore, the following hypothesis is proposed:

Hypothesis 6 (H6):

The intention to consume organic or free-range eggs positively influences the consumption behavior of organic and free-range eggs.

4. Materials and Methods

4.1. Data Collection

4.1.1. Questionnaire Design

Through a questionnaire applied to a sample of 200 Portuguese egg consumers between 27 February and 17 March 2025, we sought to understand how each factor contributes to the formation of consumption intentions and behaviors.

The questionnaire was developed following an in-depth analysis of the relevant scientific literature. The first version of the questionnaire was submitted to the qualitative “Think Aloud” technique in order to identify possible errata or improvements. The Think Aloud technique is widely used to investigate thought and decision-making processes [59]. Think Aloud [60] represents an alternative methodology that consists of having individuals verbalize their thoughts while performing a task without requiring them to introspect about them [61]. Thus, 10 respondents with different sociodemographic and economic characteristics voluntarily answered the questionnaire and presented their sincere opinion regarding it: (i) It was very extensive and repetitive; (ii) Some questions were limited to only one answer; (iii) There was a lack of specific and quantitative questions about the price factor in consumer behavior.

The new version of the questionnaire has been redesigned to be shorter, more concise and more objective, allowing for more diverse responses and including specific and quantitative questions about the impact of price on consumer behavior.

4.1.2. Measurement Scales

The items used to measure the constructs are presented below in

Table 2. Reflective scales for latent variables in proposed model.

Latent Variable	Items
Attitudes (A)	A1: I believe that consuming eggs produced organically and by free-range hens is important for the preservation of the environment.
	A2: I believe that the consumption of eggs produced organically and by free-range hens is important for animal welfare.
	A3: I think it is very important for consumers to value sustainability in their egg consumption decisions.
	A4: I believe that consuming organic eggs or eggs produced by free-range hens is more beneficial to human health.
Subjective Norms (SN)	SN1: I believe that the choice to consume organic eggs or free-range chickens is appreciated by the people closest to me.
	SN2: I believe that most of the people I live with support the consumption of organic eggs and those produced by free-range hens.
	SN3: The people who are important to me believe that I should consume organic eggs and eggs produced by free-range hens.
Environmental Awareness and Concern (EAC)	EAC1: It is important that the food I eat is produced in such a way as to avoid contamination and pollution of soil, air and water.
	EAC2: It is important that food production uses fewer resources and produces less waste.
	EAC3: Food production must be conducted without the use of harmful pesticides and synthetic chemical fertilizers.
	EAC4: It is important that the food I consume is produced by companies that promote environmental and social sustainability.
	EAC5: Today’s society seriously harms nature.
Perceived Behavioral Control (PBC)	PBC1: I think it is easy for me to have access to eggs produced in a more sustainable way (organic or free-range hens).
	PBC2: I have control over the decision to buy more sustainably produced eggs (organic or free-range hens).
	PBC3: I believe I have enough knowledge about the benefits of more sustainably produced eggs (organic or free-range hens).
Consumer Intention (I)	I1: I plan to buy eggs soon from production methods that promote animal welfare.
	I2: I intend to soon consume organic eggs or eggs from free-range hens.
	I3: I intend to consume eggs with wellness certification or organic seal.
	I4: It is my goal to consume eggs from hens fed with natural or organic feed.
Consumer Behavior (CB)	CB1: I usually consume eggs from production methods that promote animal welfare.
	CB2: I usually consume organic eggs or eggs from free-range hens.
	CB3: I usually consume eggs with animal welfare certification or an organic seal.
	CB4: I prefer to consume eggs from hens fed with natural or organic feed.

Source: Authors’ own elaboration.

. The measurement was carried out using a five-point Likert scale, which measured the degree of agreement of the respondents regarding certain statements, where 1 means “strongly disagree” and 5 means “strongly agree”. The application of this scale in the social sciences is highly recommended by researchers as it is appreciated by respondents and positively influences both response rate and quality [62]. Given the impracticality of surveying the entire Portuguese population, a non-probabilistic sample was chosen for representative convenience, so it may present slight biases. In order to ensure the best representation of the population, participation in different subgroups was encouraged, such as different genders, educational levels and income levels. The study used a non-probability sampling technique, snowball, which is often used in surveys [63]. Thus, each group of contacts of the researchers was asked to forward it to their contacts. The data was also collected in person through a QR code and the dissemination of the questionnaire on social networks. Questionnaires that did not meet the inclusion criterion (egg consumers) were excluded, yielding a valid sample of 197 respondents.

4.2. Sample Socioeconomic Description

The sample consisted of 197 respondents, all aged 18 or older, who voluntarily and anonymously completed the questionnaire. Of these, 122 were women (62%) and 75 were men (38%). The age distribution was as follows: 88 respondents (44.7%) were aged 18–27, 27 (13.7%) were 28–37, 33 (16.8%) were 38–47, 30 (15.2%) were 48–57, 18 (9.1%) were 58–67, and 1 respondent (0.5%) was aged 68 or older. Regarding professional occupation, 122 participants (62%) identified as workers, 44 (22.3%) as students, 21 (10.7%) as both working and studying, and 10 (5.1%) as unemployed. In terms of educational attainment, 78 respondents (39.6%) held undergraduate degrees, 44 (22.3%) held a master’s degree, 5 (2.5%) held a doctorate, 41 (20.8%) had completed secondary education, and 29 (14.7%) reported having only basic education. Most participants (121 individuals; 61.4%) reported living in urban areas, while 76 (38.6%) resided in rural areas. Regarding income, 94 respondents (47.7%) stated that their income was above the national average (EUR 1600 for the year 2024), 59 (29.9%) reported earning around the national average, and 44 (22.3%) indicated that their income was below the national average. Figure 2 shows the demographics of the sample.

4.3. Sample Egg Consumption and Purchase Description

Regarding egg purchase and consumption habits, most respondents reported consuming eggs from free-range hens (98; 49.7%), followed by eggs from hens raised on the ground (54; 27.4%), organic eggs (36; 18.3%), and eggs from hens raised in cages (9; 4.5%). In terms of frequency, most participants (46; 23.3%) consume eggs a few times per month; 104 (52.8%) respondents consume eggs a few times per week, while 47 (23.9%) eat them daily. As for purchase locations, the majority of respondents, 146 (74.1%), buy eggs at supermarkets or hypermarkets and 51 (25.9%) rely on their own production. 123 respondents (62.4%) and 74 respondents (37.5%) stated that price and production method (e.g., organic or free-range), respectively, were the most influential factors when purchasing eggs. Finally, it is observed that, among the 197 respondents, 30% indicated that they are not willing to pay even one additional euro for more sustainable eggs compared to conventional ones. In contrast, 50% of respondents stated that they are willing to pay up to 10% more for eggs produced through more sustainable methods. Meanwhile, 20% of consumers expressed a wtp up to 20% more for sustainably produced eggs. These results highlight a significant portion of consumers who value sustainability in egg production, with 70% showing some degree of wtp a price premium for it. Figure 3 displays these characteristics.

5. Results

After data collection, the data were analyzed using statistical research methods in R software version 4.1.1 [64], for structural equation modeling (SEM). As stated in [65], “Structural equation modeling (SEM) is a multivariate analysis method for building, estimating, and testing causal models”. SEM is used to model complex relationships between directly and indirectly observed variables [66]. According to Kline [67], a sample size of 100 to 200 is considered medium for structural equation modeling (SEM). Although complex models with numerous parameters typically require larger samples, the model employed in this study is parsimonious, making the available sample size adequate for the analysis.

First, Confirmatory Factor Analysis (CFA) was conducted to assess the constructs’ dimensionality and ensure both convergent and discriminant validity. Since the study was confirmatory in nature, the structural model was then estimated and validated using the covariance-based SEM (CB-SEM) method, supported by the TPB. The main results from the structural model estimation are reported, including the strength of the relationships between variables and their statistical significance.

5.1. Reliability and Viability

A number of latent variables are taken into account in the measurement model, including attitudes, subjective norms, perceived behavior control, environmental awareness and concern, intention, and consumer behavior. The survey items from the validated questionnaire are displayed in Table 2.

Gana and Broc [68] recommend the use of additional fit indices to evaluate model adequacy. Accordingly, the following robust fit indices were calculated for the measurement model: RMSEA = 0.060, TLI = 0.965, and CFI = 0.970. These values meet the commonly accepted thresholds, indicating a good model fit [68,69].

According to Gefen et al. [70], evaluating constructs entails assessing internal consistency reliability, convergent validity, and discriminant validity. Factor loadings and average variance extracted (AVE) are indicators of convergent validity and must fulfill certain criteria. To examine internal consistency reliability of this study, the measures composite reliability (CR) and Cronbach’s alpha are used. Results of these indicators are shown in

Table 3. Reliability and convergent validity measures.

Construct	Item	Loading	AVE	CR	Cronbach’s Alpha
A	A1	0.894	0.884	0.968	0.968
	A2	0.962
	A3	0.952
	A4	0.951
SN	SN1	0.922	0.834	0.938	0.938
	SN2	0.888
	SN3	0.93
EAC	EAC1	0.928	0.757	0.939	0.937
	EAC2	0.955
	EAC3	0.755
	EAC4	0.85
	EAC5	0.849
PBC	PBC1	0.822	0.736	0.893	0.888
	PBC2	0.902
	PBC3	0.848
I	I1	0.872	0.789	0.937	0.936
	I2	0.908
	I3	0.936
	I4	0.833
CB	CB1	0.902	0.712	0.908	0.906
	CB2	0.887
	CB3	0.81
	CB4	0.768

Source: Authors’ own elaboration.

. In this study, all the measurement items exhibit high loadings (above 0.70). An AVE of 0.50 or higher reveals the construct explains 50 percent or more of the indicators’ variance that make up the construct. In this case, the AVE indicator assumes values above 0.50 as the recommended, Moreover, all other constructs have CR and Cronbach’s alpha above the recommended value of 0.7, suggesting the high reliability of the scales [69].

To estimate the values shown in Table 3, we performed CFA, ran the Cronbach’s Alpha for each group of variables, and calculated the AVE and CR.

Table 4. Measurement results of discriminant validity.

	A	SN	EAC	PBC	I	CB
A	0.94
SN	0.634	0.914
EAC	0.858	0.564	0.87
PBC	0.68	0.853	0.58	0.858
I	0.71	0.71	0.61	0.67	0.888
CB	0.645	0.802	0.564	0.815	0.777	0.844

Note: Bold numbers in diagonal are square roots of AVE. Source: Authors’ own elaboration.

presents the correlation matrix of the analyzed variables, which is used to assess discriminant validity. Fornell and Larcker [71] suggest that the square root of the AVE of each latent variable (LV) should be greater than its correlations with any other LV in the assessment, to verify a non-significant association between them. This condition is verified, demonstrating that there is discriminant validity.

5.2. Structure Model Analysis

The regression analysis (

Table 5. Regression analysis.

Path	Unstandardized Coefficients		Standardized Coefficients		Sig.
	B	Std. Error	Beta	t-Statistics
H1: A → I	0.485	0.127	0.455	3.81	<0.001
H2: SN → I	0.376	0.127	0.443	2.955	0.003
H3: PBC → I	−0.003	0.161	−0.003	−0.016	0.987
H4: PBC → CB	0.615	0.107	0.554	5.77	<0.001
H5: EAC → I	−0.032	0.114	−0.029	−0.281	0.779
H6: I → CB	0.446	0.109	0.406	4.081	<0.001

Source: Authors’ own elaboration.

) indicates that the variables Attitudes (A) (β = 0.455, p < 0.001) and Subjective Norms (SN) (β = 0.443, p = 0.003) have a positive and statistically significant influence on individuals’ Intention (I) to consume eggs. These findings suggest that the Attitudes (A) and Subjective Norms (SN) factors play a crucial role in explaining consumer’s intentions, reinforcing their importance in the development of sustainable strategies for the sector. This validates the H1 and H2 hypothesis. In contrast, Perceived Behavioral Control (PBC) and Environmental Awareness and Concern (EAC) did not exhibit statistical significance. This result indicates that their influence within the model is limited and suggests the need to explore alternative variables that may better capture the key determinants of consumption intentions. This means that we do not validate the H3 and H5 hypothesis and living the space to explore other latent variables or the Perceived Behavioral Control (PBC) and Environmental Awareness and Concern (EAC) but captured by other variables than the ones considered in this research.

The results from the regression analysis also indicate that both Perceived Behavioral Control (PBC) and Intention (I) have a positive and statistically significant influence on the individuals Consumer Behavior (CB). The standardized coefficient for Perceived Behavioral Control (PBC) (β = 0.554, p < 0.001) suggests that higher levels of perceived control are associated with an increase in the individuals Consumer Behavior (CB). Similarly, Intention (β = 0.406, p < 0.001) also demonstrates a significant effect. These findings suggest that individuals who perceive greater control over their behavior, as well as those with a stronger intention to act, are more likely to engage in the behavior under study. This validates the H4 and H6 hypothesis. For the regression analysis performed we obtained the R-squared 0.619 when describing Intention (I) using Attitudes (A), Subjective Norms (SN), Perceived Behavioral Control (PBC), and Environmental Awareness and Concern (EAC); and the R-squared 0.775 when describing Consumer Behavior (CB) using Perceived Behavioral Control (PBC), and Intention (I). This means that, based on the knowledge of Attitudes (A), Subjective Norms (SN), Perceived Behavioral Control (PBC), and Environmental Awareness and Concern (EAC) we could explain 61,9% of the Intention (I). Similarly, based on the knowledge of Perceived Behavioral Control (PBC) and Intention (I), we could explain 77,5% of Consumer Behavior (CB).

6. Discussion

The results of the analysis indicate that factors such as consumer’s Attitudes (A) and Subjective Norms (SN) have a significant impact on the consumer’s Intention (I) to consume more sustainable eggs, such as organic and free-range eggs. The significant role of attitudes is consistent with the TPB framework, which posits that an individual’s positive or negative evaluation of a behavior is a key predictor of their intention to engage in it. These findings align with earlier research. In the context of sustainable consumption, previous research has highlighted the relevance of favorable attitudes toward environmentally friendly food products [53,72]. Consumers who perceive organic or free-range eggs as healthier, more ethical, or better for the environment are more inclined to consume such products. This attitudinal component is therefore essential to the formation of behavioral intentions and aligns with global consumption trends that increasingly prioritize animal welfare and environmental stewardship [12,22]. Likewise, the influence of subjective norms—that is, the perceived social pressure to perform or avoid a given behavior—has been widely supported in the literature. [73], in their systematic review of TPB applications in sustainable food choices, observed that attitudes and subjective norms were jointly the most frequent and robust predictors of intention in approximately 50% of the studies analyzed. In the present study, this is reflected in the fact that 49.7% of respondents preferred eggs from free-range systems, and 27.4% chose eggs from hens raised on the ground, a behavior potentially shaped by growing social endorsement of ethical consumption. These results suggest that social expectations, community values, and peer influence remain powerful levers for encouraging sustainable behavior.

However, the variables of Perceived Behavior Control (PBC) and Environmental Awareness and Concern (EAC) did not show a statistically significant relationship, suggesting that other psychological or contextual factors may play a more relevant role in the individual’s Intention (I) to consume sustainable eggs. Considering Environmental Awareness and Concern (EAC), some authors (e.g., [74]) argue that this factor alone is typically insufficient to generate strong behavioral intentions; rather, it must be transformed into a personally meaningful and actionable attitude, or become congruent with prevailing social norms, to exert a significant impact on decision-making processes. On the other hand, the lack of significant impact of Perceived Behavior Control (PBC) may indicate that, despite the positive intention, factors such as price and wtp to pay are still relevant barriers to the adoption of sustainable Consumption Behavior (CB). In fact, and according to Conner and Armitage [75], the predictive power of PBC is contingent upon the presence of perceived difficulty or control variability. The analysis of the sample revealed that price is one of the main determinants of consumer choice, with 62.4% of respondents stating that this factor directly influences the individual’s Consumption Behavior (CB) of eggs. It is also important to underline that despite not having impact on consumer’s Intention (I), Perceived Behavior Control (PBC) has a significant impact on Consumer’s Behavior (CB) regarding sustainable eggs.

The findings of this study provide valuable insights for market segmentation and the design of more effective strategies to promote sustainable food consumption, particularly concerning eggs. Given that Attitudes (A) and Subjective Norms (SN) significantly influence consumers’ Intentions (I), targeted marketing strategies should emphasize social approval and ethical values, especially among younger consumers, who tend to exhibit heightened concern for animal welfare and environmental impact.

In this regard, educational campaigns can play a pivotal role in shaping favorable evaluations of sustainable eggs by highlighting their health benefits, ethical advantages, and reduced environmental footprint. Furthermore, the mobilization of social influence mechanisms—through community-based initiatives, public endorsements, and targeted digital marketing—can enhance perceived normative pressure. For example, public commitments, consumer testimonials, and endorsements from influencers or experts may strengthen both descriptive and injunctive norms, thereby increasing the perceived social desirability of sustainable consumption behaviors [76].

Moreover, since Perceived Behavioral Control (PBC), while not significantly associated with intention, exerts a meaningful impact on actual consumption behavior, policies and interventions must address the structural and economic barriers that hinder sustainable choices, particularly price sensitivity and product availability.

Strategies such as an education campaign play a crucial role in shaping favorable evaluations of sustainable eggs by emphasizing their health benefits, ethical advantages, and environmental impact. Also, mobilizing social influence through community-based initiatives and targeted marketing can enhance perceived normative pressure. For example, public commitments and consumer testimonials can reinforce the perception that sustainable egg consumption is socially desirable and widely supported. Additionally, leveraging digital influencers, public figures, or experts to endorse sustainable consumption behaviors can activate descriptive and injunctive norms, thereby increasing the likelihood of behavioral adoption, particularly among younger consumers who are more attuned to social media cues [76].

To increase efficacy, segmented communication strategies should be adopted and marketing campaigns directed to specific profiles. For instance, environmentally aware youth may be more receptive to messaging focused on ecological responsibility and ethical production methods, while price-sensitive consumers may respond better to arguments that demonstrate how sustainable eggs can be cost-effective over time (e.g., better quality, healthier, longer-lasting). These differentiated approaches can help both the egg industry and public institutions encourage more sustainable consumption behaviors and expand the adoption of free-range and organic eggs.

Another noteworthy observation is that, although many consumers report valuing the sustainable attributes of eggs, their actual willingness to pay a premium for such products remains relatively low. This phenomenon is commonly explained by the trade-off between sustainability and cost, where consumers want to adopt sustainable behaviors, but are not always willing to afford a higher price [31,34].

The study also highlights challenges for the egg industry, which must adapt to consumer preferences without compromising the economic viability of production. The transition to cage-free farming systems has been driven by regulations and initiatives such as “End the Cage Age” [19,20], but faces challenges such as rising production costs and health risks [25]. This suggests the need for incentive policies and more accessible information to consumers to ensure an effective transition to a more sustainable consumption model [8,11].

In summary, the results reinforce the importance of considering both individual and contextual factors in promoting sustainable egg consumption. Interventions such as enhancing transparency regarding environmental impacts, implementing financial incentives, and deploying targeted educational campaigns may facilitate and promote a more effective transition toward sustainable food consumption behaviors.

7. Conclusions

This study applied a TPB extended model to understand consumer intention and behavior regarding the sustainable consumption of eggs. In addition to analyzing the influence of consumer attitudes, perceived behavioral control, and subjective norms, the expanded model incorporates environmental awareness and concern in shaping consumers’ intention to consume sustainable eggs, providing a comprehensive analytical framework.

The findings reveal that consumer attitudes and subjective norms, significantly influence the intention to consume sustainable eggs. The data also reveal that sustainable egg consumption behavior is influenced by both consumer intention and perceived behavioral control. While these results align with the international literature, they also reflect specific patterns and challenges within the Portuguese market, such as limited consumer knowledge and price sensitivity. These insights offer novel contributions by revealing both motivational and structural barriers to sustainable food choices. Stakeholders such as food producers, retailers, non-governmental organizations (NGOs), and public policymakers can leverage these findings to design more targeted campaigns and policies to foster sustainable behaviors. This research thus contributes not only to academic understanding but also to actionable strategies in a regional and potentially global context.

However, it is important to acknowledge some limitations of this study. One limitation relates to data collection, as the study is based solely on a questionnaire distributed among residents in Portugal. In the future, expanding the research to different countries and continents would provide a broader perspective, capturing insights from consumers with diverse cultural backgrounds and viewpoints. Another limitation is the limited number of variables analyzed. While this study extends the TPB model by incorporating sustainability awareness and concern adding more variables could further enhance the model’s predictive accuracy regarding sustainable egg consumption. Future studies could explore how specific demographic characteristics—such as age, educational attainment, and income level—impact the consumption patterns of sustainable eggs. For instance, researchers might investigate whether younger consumers with higher levels of education are more prone to prioritize sustainable eggs, compared to older generations. Additionally, examining the influence of income on consumption decisions could reveal whether higher earners are more willing to pay the premium prices often associated with sustainably produced eggs. Finally, the use of self-reported data may introduce some bias, as respondents might, consciously or unconsciously, provide answers that align with socially desirable norms rather than fully reflecting their actual behavior. To address this limitation, future research could complement survey responses with objective data on sustainable egg consumption, such as real purchasing records provided by producers and retailers.