Analysis of Pig Tendencies to Stay Specific Sections Within the Pig Barn According to Environmental Parameters and Facilities Features

Abstract

Pork accounts for 34% of global meat consumption, following poultry and beef. Intensive pig farming has expanded to meet increasing demand, but space constraints and poor environmental conditions can negatively affect pig welfare. This study aimed to investigate pigs’ spatial preferences in response to environmental factors in an experimental pig barn. Six 60-day-old Yorkshire pigs were observed for 60 days. Indoor temperature (IT), relative humidity (IRH), and CO₂ concentration (ICO₂) were measured hourly, and pig positions were recorded using an RGB 2D-IP camera. Pearson correlation analysis was performed using SPSS. IT ranged from 14.3 °C to 25.1 °C, IRH from 78.9% to 96.5%, and ICO₂ from 1038 to 1850 ppm. A strong negative correlation was found between IT and IRH (r = −0.89), while IT and ICO₂ were uncorrelated (r = −0.01). Pigs showed a clear preference for sections with lower IT, supporting previous findings on thermal preference. Structural features, such as two-wall enclosures, also influenced stay frequency. These results suggest that optimizing barn structure and improving ventilation and manure management can support thermal comfort and improve welfare in intensive pig farming systems.

1. Introduction

Pork is one of the most widely consumed meats globally, accounting for 34% of total global meat consumption in 2022, which is lower than poultry at 40% and beef at 22% [1]. Global pork consumption has increased significantly, rising from 63.5 million tons in 1990 to 113 million tons in 2022, a 77% growth. During the same period, poultry consumption grew by 287%, and beef consumption increased by 49%. This rising trend in meat consumption, particularly pork, is driven by global population growth and economic development, suggesting that it will continue to rise. Pork production has similarly expanded, increasing by 140% from 1961 to 2021 [2]. Further expansion of pork production is necessary to meet the growing demand.

Globally, intensive pig farming is commonly practiced, often exposing pigs to environments that cause significant stress [3,4]. For example, pigs are typically raised in confined spaces, deprived of social interaction, and provided with limited environmental enrichment, preventing them from engaging in natural behaviors such as exploration and socializing [5]. These restrictive conditions fail to meet pigs’ basic needs, leading to poor welfare and negative emotional states [6,7,8,9]. Consequently, there is growing interest in improving animal welfare in both legal and societal contexts [10]. Concerns about intensive pig farming systems, which heavily rely on methods that restrict pigs’ movement, are particularly pronounced [11,12,13,14]. Surveys and research studies have indicated public concern over such practices, emphasizing the need to provide pigs with adequate space [15,16,17].

In current farming systems, minimum space requirements based on pigs’ body weight are often not met. Space availability significantly impacts pigs’ ability to perform essential behaviors such as resting, eating, drinking, defecating, and exploring, which are crucial for their behavioral expression and welfare [18]. Lack of space can lead to nutritional and feeding-related issues, such as reduced feed conversion efficiency [19] and lower daily and final body weight gains [20]. Factors such as pig size/weight [21], group size [22], flooring type [23], ventilation system type [24], airspeed [25,26], air direction [27], and feed levels [28] interact with the housing environment, impacting pigs’ welfare, health, and productivity.

Among these factors, environmental temperature has the greatest impact on welfare, health, and productivity in pig housing. Pigs lack functional sweat glands and have a thick subcutaneous fat layer, limiting their ability to dissipate heat and making them highly sensitive to temperature changes [29]. Many studies have focused on heat stress in pigs, which typically leads to reduced feed intake as an adaptive response to minimize heat generation during digestion and metabolism. Under thermally neutral conditions, pigs prefer to rest in warmer areas and designate cooler areas for defecation [30]. Additionally, airflow and drafts influence pigs’ choice of resting and defecation sites, as drafts in resting areas can trigger abnormal defecation behaviors [31].

Many previous studies have evaluated pigs’ responses to housing conditions and assessed animal welfare based on these responses. However, these studies face challenges in accurately measuring and defining animal welfare, a complex concept encompassing both subjective and objective dimensions [32,33]. This study adopts a homeostasis-based approach to evaluate welfare, based on the definition that “an individual’s welfare is the state of its attempts to cope with its environment” [34,35]. Coping refers to the ability to maintain mental and physical stability through processes such as physiological recovery, immune defense, stress responses, and behavioral adjustments [36]. Stress responses, in particular, include biological costs that negatively impact growth, reproduction, and health maintenance [37]. Despite the critical importance of welfare, there are no established standards for validity, reliability, and sensitivity in welfare planning and evaluation, and tools that combine direct and indirect measures remain underdeveloped [38].

To address this, systems and protocols must be developed that integrate various aspects of welfare to provide a detailed and valid assessment of welfare conditions in commercial farming. Behavioral observations are crucial, as they reflect animals’ internal states and serve as early indicators of potential health problems, providing insights into their welfare [39]. Behavioral changes play an essential role in identifying health issues, and abnormal behaviors that indicate difficulty coping with the environment are considered the clearest signs of stress in pigs [40]. Therefore, monitoring animal behavior, including that of pigs, is critical to understanding their ability to adapt to their environment.

Previous studies have primarily examined the impacts of physical space and air conditions in pig housing from a macroscopic perspective. This study aims to investigate pigs’ coping strategies with their housing environment from a microscopic perspective. By dividing the housing space into specific zones, we will analyze the distribution of air conditions (air temperature, relative humidity, and carbon dioxide concentration) and structural features (ventilation fan, feeder, waterer locations, and wall configurations in each zone) and examine the relationship between these environmental factors and pigs’ preferred resting areas. This study hypothesized that pigs exhibit spatial preferences in response to environmental factors such as temperature, humidity, and CO₂ concentration, and that specific structural features of the pen may enhance or hinder these preferences. The ultimate goal is to utilize these insights to understand pigs’ coping behavior better and inform housing design strategies that improve welfare in commercial pig farming.

2. Materials and Methods

Ethics declaration

The animal experiments described in this research were conducted in accordance with the guidelines for animal experiments of Gyeongsang National University (Jinju, Korea). This research was approved by the Ethics and Animal Experimentation Committee of Gyeongsang National University (certification # GNU-150508-R0029).

Experimental pig barn characteristic

This study was conducted in an experimental pig barn at the Smart Space Sensing Laboratory (SSSL), Gyeongsang National University (latitude 35°9′6.14″ N, longitude 128°5′44.40″ E, altitude 44 m). The dimensions of the experimental pig barn were 5.4 m in length, 3.4 m in width, and 2.8 m in height. The ceiling was 5 cm thick, and the slatted floor, made of plastic material, was positioned 40 cm above the ground (Figure 1). The sidewalls of the experimental pig barn were constructed with plywood and galvanized steel, while the ceiling was made of polystyrene. These materials were selected to provide a comfortable environment for the pigs [41]. The barn was equipped with a continuously ventilated exhaust fan located opposite the main entrance at a height of 144 cm. An air damper (Auto-Damper 250, Sanison Co., Ltd., Daegu, Republic of Korea) was installed above the entrance at a height of 177 cm from the floor to ensure smooth airflow. The average airflow rate was 0.16 m³/s. The barn was divided into sections of approximately 1.5 m² each to analyze the distribution of the indoor environment (Indoor Temperature, IT; Indoor Relative Humidity, IRH; Indoor CO₂ concentration, ICO₂) and the number of pigs per zone (Figure 2). According to South Korea’s livestock land area regulations [42], the standard area for the finishing stage of five pigs is limited to 50 m². Additionally, the National Institute of Animal Science in South Korea suggests appropriate stocking densities based on pig body weight as follows: 0.24 m² per pig for 11–25 kg, 0.44 m² for 25–45 kg, 0.64 m² for 45–65 kg, 0.78 m² for 65–85 kg, and 0.91 m² for 85–110 kg [43]. The average body weight of the pigs in this study ranged from 34.7 kg to 85.9 kg, complying with both the livestock land area regulations and the guidelines provided by the National Institute of Animal Science.

Experimental Design and Data Acquisition

This study was conducted for 48 days from 16 October to 2 December 2023, using six Yorkshire pigs, which were studied from 60 days of age at the start of the experiment to 108 days of age. Environmental parameters, image data, and growth data were collected, and the experiment was carried out in a single pig barn. Environmental parameters—indoor temperature (IT, °C), indoor relative humidity (IRH, %), and indoor CO₂ concentration (ICO₂, ppm)—were measured and collected at 1-h intervals using temperature, humidity, and CO₂ sensors (MCH-383SD, Lutron, Taipei, Taiwan). During the experimental period, data stored by the sensors were extracted in a Microsoft Excel 2019 file format, and the daily average environmental data from each zone were used to calculate the Temperature-Humidity Index (THI) and Heat Index (HI) based on the official formulas of the National Weather Service (NWS).

$$THI=\left[\left(1.8\times IT\right)+32\right]-\left[0.55\times \left({\displaystyle \frac{IRH}{100}}\right)\right]\times \left[\left(\left(1.8\times IT\right)+32\right)-58\right]$$

$$\begin{array}{ll}HI=-42.379& +2.04901523\times IT+10.14333127\times IRH-0.22475541\times IT\times IRH\\ & -0.00683783\times {IT}^2-0.05481717\times {IRH}^2\\ & +0.00122874\times {IT}^2\times IRH+0.00085282\times IT\times {IRH}^2\\ & -0.00000199\times {IT}^2\times {IRH}^2\end{array}$$

where IT is the indoor temperature in °C and IRH is the indoor relative humidity in %.

The sensors were installed at the center of each 12 sections, positioned 70 cm above the floor. As described in

Table 1. Pig food components (%) and energy (kcal) provided to pigs (Growing pigs late feed 10).

Components	Composition
Fat (crude)	>4.5
Ash (crude)	<8
Protein (crude)	<18
Fiber (crude)	<10.0
Calcium	>0.5
Lysine	>0.9
Crude protein (digestible)	>12.0
Phosphorus	<1.2
Phosphorus	<1.2
Energy (digestible)	3500

, feed (G Max Care for sows and growing pigs, Nonghyup Co. Ltd., Seoul, Republic of Korea) was provided twice daily at 9:00 a.m. and 5:00 p.m. using an automatic feeder, with a feed amount of 5% of the pigs’ average body weight [36], while pigs had free access to water through drinkers. The facilities in each of the 12 sections were categorized based on the presence of feeders, drinkers, and ventilation fans into the feeder section (FS), drinker section (DS), and ventilation fan section (VFS). Additionally, the structural characteristics of the zones were assigned based on the number of walls as none wall section (NWS), one wall section (OWS), and two walls section (TWS) (

Table 2. Facility features assigned to each section (VFS: Ventilation fan section; FS: Feeder section; DS: Drinker section; TWS: Two walls section; OWS: One wall section; NWS: None wall section).

Section	Facilities Features
	Facilities	Wall
A	None	TWS
B	VFS	OWS
C	None	TWS
D	FS	OWS
E	None	NWS
F	DS	OWS
G	FS	OWS
H	None	NWS
I	DS	OWS
J	None	TWS
K	None	OSW
L	None	TWS

). Considering the pigs’ natural behavior of separating defecation and resting areas, the barn was cleaned every 14 days based on the amount of manure accumulated on the floor [44,45,46]. An RGB-2D IP camera (Super 4MP camera, ASECAM, Shenzhen, China) was used to monitor the pigs’ positions. Due to restrictions from other equipment, the camera was installed on the side of the experimental pig barn. Video footage captured by the camera was stored on a laptop’s hard drive, and image data were extracted from the videos at 1-h intervals. Growth data were collected manually by measuring the weight of all pigs twice daily at 9:00 AM and 5:00 PM using a portable scale (CAS Co. Ltd., Gunpo, Republic of Korea).

Data Analysis

Data preprocessing involved removing missing values and outliers using the interquartile range (IQR) method. Subsequently, environmental parameter data were matched with the sections where the highest number of pigs was observed at corresponding times. Environmental data and pig position data were averaged on a daily basis to reduce random fluctuations and sensor noise inherent in hourly readings. This approach allowed for a more stable representation of environmental conditions and their cumulative influence on pigs’ spatial preferences, although it limits the ability to analyze temporal patterns within the day. All statistical analyses, including Pearson correlation analysis, were performed using IBM SPSS Statistics (IBM SPSS Statistics 22.0.0.0, IBM, NY, USA). Pearson correlation was selected due to the continuous nature of the variables and the objective of assessing linear relationships between environmental parameters and pig staying frequencies across different sections. Graphical illustrations were prepared using Origin Pro 9.5.5 (OriginLab, Northampton, MA, USA).

3. Results and Discussions

3.1. Summary of Environmental Parameters Inside the Experimental Pig Barn and Growth of Pigs

3.1.1. Environmental Parameters Overview

The average environmental parameters inside the experimental pig barn during the 48-day study period are presented in Figure 3. The highest indoor temperature (IT) recorded was 25.1 °C, while the lowest was 14.3 °C, with a standard deviation of 2.9 °C. These values slightly deviate from the optimal range of 16–25 °C recommended by Dong et al. [47] for pig rearing in experimental facilities. This deviation is likely attributable to periodic manure cleaning and the operation of temperature, humidity, and CO₂ sensors during the experimental period, which may have temporarily affected environmental conditions. Indoor relative humidity (IRH) varied between 78.9% and 96.5%, with a standard deviation of 4.6%. Indoor CO₂ concentration (ICO₂) ranged from an average low of 1037.9 ppm to a high of 1850.2 ppm, with a standard deviation of 256.0 ppm. The temperature-humidity index (THI) showed a maximum of 68.9, a minimum of 57.9, and a standard deviation of 2.9.

3.1.2. Correlation Analysis of Environmental Parameters in the Experimental Pig Barn

Figure 4 shows the correlations among the average environmental parameters. A strong negative correlation was observed between IT and IRH (r = −0.89), reflecting the inverse relationship between temperature and relative humidity. No significant correlation was found between IT and ICO₂ (r = −0.01, p = 0.484) or between IRH and ICO₂ (r = 0.16, p = 0.140), indicating that CO₂ concentration varied independently of temperature and humidity in this setting. Previous studies have demonstrated that ventilation rates contribute to reducing indoor CO₂ concentrations [48], whereas CO₂ emissions increase with manure accumulation [49]. Additional factors such as pig respiration rate, activity level, and body weight are also known to influence indoor CO₂ levels [50]. In this study, ICO₂ levels sharply decreased immediately following manure cleaning and gradually increased over time (Figure 3), highlighting the significant impact of manure accumulation on CO₂ concentration. The ventilation fans used had an airflow rate of 0.16 m³/s, substantially lower than the recommended range of 0.38 to 0.47 m³/s for experimental pig barns [51]. This limited airflow likely reduced ventilation effectiveness in lowering CO₂ levels. In contrast, the effect of manure cleaning and ventilation on IRH was minimal, consistent with previous findings that IRH is influenced by a complex interplay of temperature, ventilation rates, manure amount, and pig weight [48].

3.1.3. Analysis of Body Weight and Average Daily Gain(ADG) During the Experimental Period

Figure 5 illustrates the body weight changes of the six experimental pigs throughout the study. Their weights ranged from 34.7 kg to 85.9 kg, with an average standard deviation of 5.9 kg (maximum 7.0 kg, minimum 4.8 kg). The average daily gain (ADG) was 1.1 kg. According to [52], typical ADG values are 0.6 kg/day during the growing phase (20–50 kg), 0.86 kg/day during the early finishing phase (50–75 kg), and 0.9 kg/day during the late finishing phase (75–110 kg). The ADG observed in this study exceeded these benchmarks by approximately 0.2 kg, likely reflecting the low stocking density in the experimental barn compared to commercial farms. ADG can vary according to breed, sex, nutrition, disease status, and housing conditions. In particular, ref. [53] emphasizes that feed allocation tailored to the growth stage and appropriate management of the rearing environment are critical factors influencing ADG.

3.2. Summary of Environmental Parameters by Section

Figure 6, Figure 7, Figure 8, Figure 9 and Figure 10 present the average values of indoor relative humidity (IRH), indoor temperature (IT), indoor CO₂ concentration (ICO₂), temperature-humidity index (THI), and heat index (HI) measured in each section of the experimental pig barn during the study period. Figure 11, Figure 12, Figure 13, Figure 14 and Figure 15 further illustrate the spatial distribution of these environmental parameters across the 12 sections using a 4×3 matrix format. Significant differences were observed among sections for all environmental variables (p < 0.05), suggesting that environmental conditions varied depending on structural features and the relative location within the barn. The average IRH across all sections was 76.5%. Seven sections (C, F, H, I, J, K, and L) recorded IRH values above this average. The highest IRH was observed in Section J (87.4%), which had no equipment and was enclosed by two walls (TWS). Similar TWS structures in Sections C and L also exhibited high IRH values (84.1% and 85.7%, respectively), whereas Section A, despite having the same wall configuration, showed a relatively lower IRH (62.9%). In general, sections located farther from the ventilation fan and closer to the water source tended to have higher humidity, likely due to reduced air circulation and localized moisture accumulation. The average IT across all sections was 19.8 °C. Seven sections (A, B, C, H, J, K, and L) recorded temperatures above the overall average. Section A had the highest IT (21.8 °C), followed closely by Section J (21.7 °C), both featuring TWS designs. The elevated temperatures in these sections may be attributed to restricted airflow caused by wall enclosures and distance from the ventilation fans. Interestingly, Sections B and C, located near the ventilation fan, also recorded higher IT values, potentially due to higher pig occupancy and associated metabolic heat generation. The average ICO₂ concentration across all sections was 1406.6 ppm. Six sections (A, B, C, H, J, and L) exceeded this average, with Section J recording the highest concentration (1553.8 ppm). The high CO₂ level in Section J is likely related to its enclosed structure and poor ventilation efficiency. Despite its similar TWS design, Section L was adjacent to the control room and other open areas, which may have facilitated better air exchange and slightly reduced CO₂ accumulation. These findings suggest that both structural layout and spatial context influence ventilation performance and gas buildup. The average THI across all sections was 63.4. Six sections (A, B, C, J, K, and L) showed THI values above this average. Section J again had the highest THI (70.5), corresponding with its elevated IT, IRH, and ICO₂ levels. Since THI is derived from temperature and humidity, its elevation in Section J reinforces the notion that this section experienced the most thermally loaded environment. Although none of the sections exceeded the THI threshold for heat stress (THI ≥ 74) defined by Mengbing Cao et al. (2021) [54], pigs in these high-THI areas may still have experienced suboptimal comfort. The preference of pigs for lower-THI sections observed in subsequent analysis supports this interpretation. The average HI across all sections was 76.1. Seven sections (A, B, D, E, G, I, and J) recorded values above this average, with Section G showing the highest HI (80.0). Interestingly, Section G had relatively low IT and IRH but still yielded the highest HI, indicating that HI may overestimate thermal stress under certain conditions. Moreover, Section G recorded the lowest THI (61.8), highlighting a potential inconsistency between the two indices. These results support previous findings [55] that THI, rather than HI, provides a more reliable estimate of animal thermal comfort in livestock housing. Collectively, these findings indicate that structural design, such as the number of enclosing walls and proximity to ventilation sources or water lines, plays a critical role in shaping the microenvironment within pig barns. These environmental differences, in turn, influence pigs’ spatial preferences, as discussed in the subsequent section.

3.3. Number of Pigs Staying in Each Section According to Facility and Structural Features

Figure 16 presents the frequency of pig presence in each section, based on image data extracted at time points synchronized with the environmental parameter measurements. The section with the highest number of observed stays was Section A, with 381 counts, whereas Sections E and H recorded no pig presence throughout the experimental period. Section A, which recorded the highest stay frequency, featured no equipment and was enclosed by two walls (Two-Wall Structure, TWS). Other sections with similar structural characteristics—Section C (105 stays), Section J (150 stays), and Section L (93 stays)—also showed relatively high frequencies of pig presence. These findings suggest that pigs may prefer enclosed environments that offer a sense of protection or reduced disturbance, consistent with the idea that wall-enclosed areas provide a form of environmental refuge. Notably, although Section J exhibited the highest values for THI and CO₂ concentration, pigs were still observed with moderate frequency in this section (150 stays). This suggests a potential behavioral trade-off between thermal discomfort and psychological refuge provided by the two-wall enclosure. Such findings imply that pigs’ spatial choices are shaped not only by environmental variables but also by structural features offering a sense of safety. When pig stay frequency was analyzed by facility type, dry space (DS; Sections F and I) accounted for a total of 231 stays, while the feeding space (FS; Section G) and ventilation fan space (VFS; Section B) each recorded only 42 stays. Sections without specific facility features (A, C, D, E, H, J, K, and L) collectively recorded 837 stays. This implies a general preference for structurally simple or open areas, particularly those without feeding or ventilation equipment. Average stay frequencies per section were calculated to adjust for the number of sections in each category. DS sections had 115.5 stays per section, FS and VFS each had 42 stays, and sections without specific facility features averaged 104.6 stays per section. These values further support the interpretation that pigs favored TWS designs and open or dry spaces, potentially due to increased thermal comfort, reduced noise, and minimal human or mechanical disturbance. Overall, the results indicate that pigs exhibit distinct spatial preferences influenced not only by environmental parameters but also by the structural and functional characteristics of their surroundings. These findings highlight the importance of considering both environmental and architectural factors in the design of welfare-oriented pig housing.

3.4. Environmental Parameters and Pig Presence by Section

The relationship between environmental parameters and the frequency of pig presence in each section was analyzed using Pearson correlation analysis, as shown in

Table 3. Correlation table of section-wise pig staying count and environmental parameters.

Parameters		Correlation Coefficient (r)	p-Value
Counts pigs	IRH	−0.02	< 0.05
	IT	−0.39	< 0.001
	ICO2	−0.24	< 0.001
	THI	−0.38	< 0.001
	HI	−0.18	< 0.001

. The results revealed a statistically significant negative correlation between indoor temperature (IT) and pig presence (r = −0.39, p < 0.001), indicating that pigs tended to prefer sections with relatively lower air temperatures. This finding is consistent with previous studies reporting that pigs seek out cooler environments under thermoneutral conditions to regulate body temperature [30]. Moreover, not only ambient air temperature but also floor surface temperature has been identified as a key factor affecting pigs’ thermoregulatory behavior [56,57]. Relative humidity (IRH) showed a negligible and statistically non-significant correlation with pig presence (r = −0.02, p < 0.05), suggesting that within the measured range, humidity levels did not strongly influence pigs’ choice of resting areas. This may be due to the relatively narrow variation in humidity observed during the experiment or pigs’ relatively low sensitivity to moderate humidity changes compared to temperature. Indoor CO₂ concentration (ICO₂) was also significantly correlated with pig presence (r = −0.24, p < 0.001), indicating that pigs tended to avoid areas with higher CO₂ levels. Although the recorded CO₂ concentrations in this study (maximum 1553.8 ppm) were well below thresholds associated with respiratory distress (typically >40,000 ppm), elevated CO₂ levels may reflect poor ventilation or the accumulation of other gases that contribute to suboptimal air quality. Thus, the observed pig position may reflect an avoidance response to inadequate ventilation rather than to CO₂ per se. The temperature-humidity index (THI), which combines air temperature and relative humidity to estimate thermal stress, also showed a significant negative correlation with pig presence (r = −0.38, p < 0.001). According to the classification by Mengbing Cao et al. (2021) [54], THI values below 74 are considered suitable for pig housing, while values above this threshold indicate varying levels of heat stress. In this study, all THI values remained below 74; however, sections with relatively higher THI values still recorded lower pig presence. This suggests that pigs are behaviorally responsive to even moderate thermal load differences within non-stressful ranges. Finally, the heat index (HI) also exhibited a weak but statistically significant negative correlation with pig presence (r = −0.18, p < 0.001). However, as previously discussed, HI values did not consistently align with other environmental measures or pig position data and may not be a reliable indicator for assessing thermal comfort in pigs. Overall, the results highlight that pigs actively select microenvironments that offer relatively lower temperatures and improved air quality. These behavioral tendencies should be considered when designing pig housing systems, especially with regard to ventilation layout, structural configuration, and localized thermal management.

4. Conclusions

This study analyzed the effects of various environmental parameters—including indoor temperature (IT), indoor relative humidity (IRH), temperature-humidity index (THI), heat index (HI), and indoor CO₂ concentration (ICO₂)—on pigs’ preferences for resting areas within a barn. The findings underscore the importance of a multidimensional environmental assessment that goes beyond the conventional focus on temperature and humidity.

A strong negative correlation was observed between IT and the number of pigs present (r = −0.39, p < 0.001), indicating a clear preference for cooler areas. Similarly, lower THI, ICO₂, and HI values were associated with higher frequencies of pig presence (r = −0.38, −0.24, and −0.18, respectively; all p < 0.001). These results suggest that pigs’ spatial distribution can serve as a practical, non-invasive indicator of thermal comfort and may inform welfare-centered environmental design in swine housing.

Future environmental strategies should go beyond simple temperature regulation to effectively enhance animal welfare and productivity. This includes improving ventilation to manage CO₂ levels, optimizing structural configurations to facilitate heat dissipation, and implementing localized cooling systems. In particular, pigs’ observed preference for sections bordered by two walls (Sections A, C, J, and L) highlights the potential role of enclosure and perceived safety in influencing spatial behavior, which should be considered in housing design.

This study has several limitations. It did not evaluate the duration of stay or specific resting postures and was conducted under controlled conditions using only plastic slatted flooring. Future research should explore a wider variety of flooring materials (e.g., concrete, rubber mats, floor cooling systems, and deep litter) and apply video-based behavioral analysis to quantify residence time and classify postural behaviors. Additionally, since thermal comfort needs vary by growth stage (e.g., piglets, growers, and sows), age-specific environmental strategies should be developed.

Moreover, incorporating time-series analysis of environmental and behavioral data across different times of day (e.g., morning, afternoon, and night) could provide valuable insights into diurnal behavioral patterns and support the development of adaptive environmental control strategies. The integration of artificial intelligence (AI) and machine learning, particularly for behavior classification and predictive modeling using image and sensor data, holds strong potential for real-time welfare monitoring and autonomous decision-making in pig barn management.

Ultimately, the findings from this study provide a foundation for designing smarter, animal-centered housing systems that are both scientifically grounded and practically applicable in commercial farming environments.