Search Results (65)

Cannibalism in Black-necked pheasants is a problem in aviary rearing, and an effective solution is still lacking. We performed the present study to investigate the potential of using tryptophan or silymarin to suppress cannibalism. The following types of investigations were performed: evaluation of the pheasants’ harmful behavior manifestations, and evaluation of the clinical forms, severity and localization of injuries of feathers and tissues, and neurohormonal manifestations. Additionally, the potential of cannibalism control in pheasants by supplementing tryptophan and silymarin to the birds’ diet was investigated. Ethological studies have shown a low intensity of feather pecking in pheasants without cannibalism manifestations. In pheasants with pronounced cannibalism, severe forms of feather and tissue pecking were observed in the head, back, wings, and rump areas, as well as specific forms affecting the tail feathers and the cloaca. Tryptophan and silymarin significantly reduced the levels of injurious pecking in the studied game birds and improved the healing of the lesions. The blood serotonin and dopamine levels in pheasants manifesting cannibalism were significantly lower than those in birds which did not show such behavior. The addition of tryptophan or silymarin to the diet of birds exhibiting cannibalism resulted in significantly increased plasma concentrations of serotonin or dopamine. Full article

Foraging behavior in hens is an important indicator of animal welfare. It involves both the search for food and exploration of the environment, which provides necessary enrichment. In addition, it has been inversely linked to damaging behaviors such as severe feather pecking. Conventional studies rely on manual observation to investigate foraging location, duration, timing, and frequency. However, this approach is labor-intensive, time-consuming, and subject to human bias. Our study developed computer vision-based methods to automatically detect foraging hens in a cage-free research environment and compared their performance. A cage-free room was divided into four pens, two larger pens measuring 2.9 m × 2.3 m with 30 hens each and two smaller pens measuring 2.3 m × 1.8 m with 18 hens each. Cameras were positioned vertically, 2.75 m above the floor, recording the videos at 15 frames per second. Out of 4886 images, 70% were used for model training, 20% for validation, and 10% for testing. We trained multiple You Only Look Once (YOLO) object detection models from YOLOv9, YOLOv10, and YOLO11 series for 100 epochs each. All the models achieved precision, recall, and mean average precision at 0.5 intersection over union (mAP@0.5) above 75%. YOLOv9c achieved the highest precision (83.9%), YOLO11x achieved the highest recall (86.7%), and YOLO11m achieved the highest mAP@0.5 (89.5%). These results demonstrate the use of computer vision to automatically detect complex poultry behavior, such as foraging, making it more efficient. Full article

FP is a detrimental behavior for chickens, ducks, and geese associated with numerous physiological and neurobiological characteristics, which have been identified in many species as regulated by the gut microbiota. However, it is unknown whether and how gut microbiota influences FP by regulating neurotransmitter systems in geese. This study aimed to investigate the phenotypic correlation between feather pecking and changes in physiological, neurobiological, and gut microbiota profiles in gosling. Three behavioral phenotypes were observed in goslings, including severe feather peckers (SFPs), victims of SFPs, and non-peckers (NFPs). The significantly lower feather scores and body weights were observed in victims compared to both SFPs and NFPs (p < 0.05). Regarding the physiological phenotype, victims had higher dopamine (DA) levels than NFPs, and SFPs had lower 5-hydroxytryptamine (5-HT) in the serum than NFPs (p < 0.001), with intermediate 5-HT levels in victims. Victims had lower glutathione peroxidase (GSH-Px) compared to SFPs and NFPs (p < 0.05). Moreover, higher mRNA expression levels of HTR1A, SLC6A4, and TPH2 in the 5-HT metabolic pathway were detected in NFPs than those in SFPs and victims (p < 0.05). In addition, regarding gut microbiota measured by 16S rRNA sequencing, SFPs had lower diversity and comparable cecal microbiota compared to victims and NFPs. Proteobacteria, Verrucomicrobia, Ruminococcus spp., and Bilophila spp. were enriched in SFPs, while Bacteroides and Parabacteroides were enriched in NFPs. From the predicted bacterial functional genes, the cAMP signaling pathway, cGMP–PKG signaling pathway, and pyruvate metabolism were activated in SFPs. The correlation analysis revealed that the genera Bacteroides spp. were associated with differences in 5-HT metabolism between the SFPs and NFPs. In summary, differences in the cecal microbiota profile and 5-HT metabolism drive FP phenotypes, which could be associated with the reduced gut abundance of the genera Bacteroides spp. Full article

Environmentally modified housing [EMH; windowless, insulated sidewalls and ceiling, thermostatically controlled ventilation fans) versus conventional housing [CVH; cross-ventilated, insulated ceiling, ceiling fans) improved broiler performance in the summer. The objective of this investigation was to determine whether social behaviors differed between two population densities (0.06 m²/chick [HD] or 0.07 m²/chick [LD]) in these houses. We used a randomized block statistical design, involving houses, population densities, observation times, and bird age. Behaviors were observed weekly, during the morning and the afternoon. Individual observers focused on the group of broilers in one of three defined 26.76 m² areas in each of the four pens in each house. Aggressive encounters, tail and back pecking, feather eating, thermoregulatory, preening, and flock mobility were recorded. Feather pecking, eating and aggressive encounters were expressed at greater rates in HD birds in CVH. A salt-deficient diet caused increased feather pecking and aggressive encounters, which decreased after correction of the mistake. Increased heat indices (HIs), HD, and greater light intensity in CVH influenced behaviors and mortality more severely than in EMH. In CVH and EMH, burrowing/thermoregulatory/resting activity increased with increasing HIs. Afternoon preening was elevated significantly in EMH. It was concluded that broilers reared in EMH were more comfortable and experienced improved welfare compared to those reared in CVH. Full article

The behavior of floor-raised chickens is closely linked to their health status and environmental comfort. As a type of broiler chicken with special behaviors, understanding the daily actions of yellow-feathered chickens is crucial for accurately checking their health and improving breeding practices. Addressing the challenges of high computational complexity and insufficient detection accuracy in existing floor-raised chicken behavior recognition models, a lightweight behavior recognition model was proposed for floor-raised yellow-feathered chickens, based on a Dual-Backbone Heterogeneous YOLO Network. Firstly, DualHet-YOLO enhances the feature extraction capability of floor-raised chicken images through a dual-path feature map extraction architecture and optimizes the localization and classification of multi-scale targets using a TriAxis Unified Detection Head. Secondly, a Proportional Scale IoU loss function is introduced that improves regression accuracy. Finally, a lightweight structure Eff-HetKConv was designed, significantly reducing model parameters and computational complexity. Experiments on a private floor-raised chicken behavior dataset show that, compared with the baseline YOLOv11 model, the DualHet-YOLO model increases the mAP for recognizing five behaviors—pecking, resting, walking, dead, and inactive—from 77.5% to 84.1%. Meanwhile, it reduces model parameters by 14.6% and computational complexity by 29.2%, achieving a synergistic optimization of accuracy and efficiency. This approach provides an effective solution for lightweight object detection in poultry behavior recognition. Full article

Feather pecking (FP) is a significant welfare and economic problem in laying hen husbandry. While there is growing evidence that the glutamatergic system plays a crucial role in regulating FP behavior, the biological mechanisms remain unclear, largely due to the limited uptake of peripheral glutamate across the blood–brain barrier (BBB). Here, we applied a multi-omics approach combined with physiology assays to answer this question from the perspective of the gut–brain axis. A total of 108 hens were randomly assigned to two groups (treatment and control) with six replicates each, and the treatment group was subjected to chronic environmental stressors including re-housing, noise, and transport. We found that chronic exposure to environmental stressors induced severe FP, accompanied by reduced production performance and increased anxiety- and depression-related behaviors, compared to controls. In addition, the immune system was potentially disrupted in FP chickens. Notably, gut microbiota diversity and composition were significantly altered, leading to decreased microbial community stability. Non-targeted metabolomic analysis identified a variety of differential metabolites, primarily associated with arginine and histidine biosynthesis. A significant increase in glutamate levels was also observed in the hippocampus of FP chickens. Transcriptome analysis revealed the upregulated expressions of glutamate-related receptors GRIN2A and SLC17A6 in the hippocampus. Correlation analysis indicated that GRIN2A and SLC17A6 are positively associated with arginine levels in the duodenum, while Romboutsia in the duodenum is negatively correlated with arginine. These findings suggest that intestinal bacteria, including Romboutsia, may influence FP behavior by altering plasma arginine and histidine levels. These changes, in turn, affect glutamate levels and receptor gene expression in the hippocampus, thereby regulating the glutamatergic system. Our research offers insights into novel strategies for mitigating harmful behaviors in poultry farming, with potential benefits for animal performance and welfare. Full article

Feather pecking can influence the welfare and health concerns of all farmed poultry and affect production and economic aspects. Although some information is available about feather pecking behavior in chickens and ducks, the risk factors of feather pecking in goslings have not been fully demonstrated. In this study, 3-day-old Yangzhou goslings were chosen, and risk factors of feather pecking injurious behavior were investigated, including stocking density, rearing method, flock uniformity, and environmental enrichment. The gosling performed three different pecking behaviors in starter barns from 3d of age to 10d, including gentle feather pecking (GFP), severe feather pecking (SFP), and aggressive pecking (AGP), and the corresponding proportions were 82.16%, 17.02%, and 0.82%, respectively, with peak aggressive feather pecking at 4–5 days of age. The pecked gosling also led to further pecking by conspecifics. Goslings preferred to peck the back (77.32%) and head (11.14%), which caused skin damage to the epidermal and dermal layers, accompanied by a decrease in feather follicle number and diameter. In addition, the effect of the stocking density and population uniformity on the occurrence of feather pecking was determined. The higher feather pecking frequencies and poorer feather quality of goslings were observed under high-density conditions than those of lower-density environments. Importantly, the lower population uniformity resulted in more aggressive pecking, potentially linked to the establishment of a social hierarchy. Finally, environment-related changes in pecking behavior were investigated. The results showed that damp and dirty housing conditions deteriorated plumage conditions and the occurrence of feather pecking, and environment enrichment (the grass section) could significantly reduce the incidence of pecking. Taken together, lower stocking density, higher population uniformity, and the provision of enrichment can reduce the prevalence of feather pecking. Meanwhile, feather pecking in goslings, with the back being the most commonly targeted area, can lead to the loss of back feathers and even skin damage. These results help to develop effective management and prevention strategies to reduce the negative effects of pecking behavior on goose health and performance. Full article

Recently, free-range poultry production has increased with notable benefits for animal welfare and meat quality traits. Geese, the third-most productive poultry species, have not been studied extensively. This study investigated the effects of different free-range systems on muscle fiber characteristics and welfare status (feather quality, walking ability, and behavioral changes) in Yangzhou geese. A total of 180 male geese, aged 28 days, were randomly assigned to either a long-distance pasture system (LDPS, approximately 200 m from the geese house) or a short-distance pasture system (SDPS, approximately 50 m from the geese house). The indoor system (IS) treatment was used as a control. And all geese were equipped with pedometers. Daily step counts revealed that the geese took an average of 5777 and 4520 steps in the LDPS and SDPS, respectively, whereas only 2736 steps in the IS. Although no significant differences were observed in the muscle fiber types among the three systems, free-range systems contributed to more developed muscle fibers than the IS. In addition, thicker muscle fibers in the extensor digitorum longus and gastrocnemius muscles were observed in the LDPS group than in the SDPS group. Additionally, feather cleanliness and damage were evaluated. LDPS resulted in significantly cleaner feathers on the chest, abdomen, and back than the IS. Furthermore, geese in the free-range systems had less feather damage than those in the IS. Notably, pasture systems allowed for natural behaviors, such as single-foot standing, feather pecking, and walking, regardless of grazing distance. Taken together, these results show that the muscle fibers of geese in the free-range system were more developed. Simultaneously, increasing the amount of exercise for geese will improve their welfare, which is beneficial to their health, growth, and development, and provides a technical reference for the free-range breeding system for geese. Full article

As animal welfare becomes more active in livestock industry, research is being conducted on ways to improve poor housing environments, reduce stress, and meet welfare standards. Among these, environmental enrichment methods are effective in reducing stress and creating a welfare-friendly rearing environment, but there are few cases of actual application to farms. Therefore, we aimed to investigate the effect of providing pecking materials (grain blocks), known as one of the environmental enrichment methods, to commercial broiler farms. This study used two facilities that could accommodate 32,000 one-day-old broilers (Arbor acres) per building, and two groups (control and treatment groups) were designed after creating two identical areas within each building (total two treatments, two replicates, 16,000 birds per replicate). Two identical zones within the house were created by installing a partition in the center; one side was provided with grain blocks (one grain block per 1000 birds), and the other side was not. Analysis items included productivity (body weight, uniformity), environmental variables (litter and air), welfare indicators (leg, gait score, feather cleanliness score), and serum corticosterone levels. Analysis of all items was conducted twice, on the 19th and 27th, taking into account the farm’s feed change date and slaughter schedule. Other environmental conditions (density, lighting, ventilation, temperature, humidity, feed, and water) were the same. As a result, no difference in productivity was observed according to enrichment, and the quality of litter and air was similar. Also, there was no significant difference in welfare indicators. Interestingly, however, provision of the environment enrichment lowered serum corticosterone levels (p < 0.05). The implications of our study are that grain blocks as a pecking material are an effective way to reduce stress without adversely affecting broiler performance and rearing environment. However, it is still necessary to explore optimal enrichment materials that can help not only the welfare level but also the broiler performance. Full article

The aim of this study was to evaluate the effect of the origin of hens of locally adapted breeds on the levels of selected stress indicators and neurotransmitter serotonin in blood, and also on the selected behaviour and plumage condition. A total of 168 one-day-old chicks of the hens Leghorn H-22, Sussex S-66 and Rhode Island Red R-11 were allocated to three experimental groups, respectively: 1, 2 and 3. The birds were reared on litter until 64 weeks of age. Bird mortality was monitored during the experiment, the duration of tonic immobility (TI) was measured and blood was collected and the following were determined: heterophil-to-lymphocyte ratio (H:L), levels of corticosterone, adrenaline, noradrenaline and serotonin. Behavioural observations were also made and the plumage condition of the hens was also assessed. The hen strains studied showed different levels of fear and stress during rearing, as reflected in the behavioural test carried out and the blood levels of basal corticosterone, noradrenaline and the H:L ratio. It was also shown that changes in the birds’ fear and stress response strategies can occur with age. H-22 hens showed greater fear and stress at both young age and adulthood, and were characterised by poorer plumage and higher mortality during rearing. The results, therefore, suggest that strain H-22 has a greater propensity to develop stereotypes such as feather pecking compared to strains S-66 and R-11. Full article

The hypothalamic–pituitary–adrenal (HPA) axis responsivity is influenced by early life experience and also modified by the environment an individual experiences as an adult. Because laying hens are transferred from rearing to laying farms at 16–18 weeks of age, they are well suited to study the interaction effect between early (rearing) and adult (laying) environments on physiology and behaviour. In the European Union, there is a move towards cage-free systems for laying hens, but globally, the majority of layers are kept in conventional or furnished cages. Conventional cages have no enrichment, whereas furnished cages have little enrichment. Both cage types limit the movement of birds and the expression of highly motivated behaviours. Lack of enrichment may lead to under-stimulated birds that are more sensitive to stress and fear-inducing challenges later in life. Fearfulness has been linked to feather pecking, which has negative consequences for animal welfare and productivity. Previous research has shown that birds reared in cages are more fearful and perform more poorly in a test of spatial cognition than birds reared in aviaries when tested within five weeks after transition to adult housing. However, recent results suggest that these effects might not be long-lasting. We, therefore, tested the effect of the early (rearing) (aviary vs. cage) and adult (laying) environments (standard vs. additionally enriched furnished cages) on the corticosterone response to restraint in birds that were 35 weeks into lay (i.e., 52 weeks of age) and assessed their plumage condition. We hypothesised that a lower level of enrichment, both during rearing and adulthood, would represent a lower level of stimulation, resulting in a stronger corticosterone response to restraint and poorer feather cover. Both stressed (restrained) and control birds increased their corticosterone levels from the first (baseline) to second sample (p < 0.01 for both), but the increase in the restrained group was significantly higher than in the control group (F_{1, 111} = 9.51; p = 0.003). There was no effect of the early environment, but birds housed in standard furnished cages as adults had overall higher corticosterone levels than birds housed in enriched furnished cages regardless of their early life environment (F_{1, 51} = 4.12; p = 0.048). Neither early nor adult housing influenced the feather score except for on the belly, where birds housed in enriched cages as adults had a poorer feather score, contrary to our prediction. In conclusion, no effect of the early environment on HPA axis responsivity to an acute stressor could be detected at 52 weeks of age, but adult enrichment had a favourable effect on overall corticosterone levels. Full article

Numerous studies have evidenced that neuropsychiatric disorders (mental illness and emotional disturbances) with aggression (or violence) pose a significant challenge to public health and contribute to a substantial economic burden worldwide. Especially, social disorganization (or social inequality) associated with childhood adversity has long-lasting effects on mental health, increasing the risk of developing neuropsychiatric disorders. Intestinal bacteria, functionally as an endocrine organ and a second brain, release various immunomodulators and bioactive compounds directly or indirectly regulating a host’s physiological and behavioral homeostasis. Under various social challenges, stress-induced dysbiosis increases gut permeability causes serial reactions: releasing neurotoxic compounds, leading to neuroinflammation and neuronal injury, and eventually neuropsychiatric disorders associated with aggressive, violent, or impulsive behavior in humans and various animals via a complex bidirectional communication of the microbiota–gut–brain (MGB) axis. The dysregulation of the MGB axis has also been recognized as one of the reasons for the prevalence of social stress-induced injurious behaviors (feather pecking, aggression, and cannibalistic pecking) in chickens. However, existing knowledge of preventing and treating these disorders in both humans and chickens is not well understood. In previous studies, we developed a non-mammal model in an abnormal behavioral investigation by rationalizing the effects of gut microbiota on injurious behaviors in chickens. Based on our earlier success, the perspective article outlines the possibility of reducing stress-induced injurious behaviors in chickens through modifying gut microbiota via cecal microbiota transplantation, with the potential for providing a biotherapeutic rationale for preventing injurious behaviors among individuals with mental disorders via restoring gut microbiota diversity and function. Full article

A complex system of neural pathways, collectively known as the microbiota–gut–brain (MGB) axis, interconnects the gut microbiota, the gastrointestinal system, and the brain along with its periphery. Previous studies have demonstrated that modulation of the MGB axis can influence stress-related behaviors such as anxiety. This connection becomes apparent in scenarios like agonistic behavior in laying hens, which is characterized by aggressive head and feather pecks, that can ultimately result in cannibalism and death. The objective was to examine the effects of a dietary synbiotic on agonistic behavior, plasma and brain monoamines, stress parameters, and cecal microbiota counts via modulation of the MGB axis. A total of 396 W36 Hy-Line laying hens were provided at random with a control (CON: basal diet) or treatment (SYN: basal diet supplemented with synbiotic) diet from 50 to 60 weeks old (nine pens/treatment, 22 birds/pen). Blood samples and video recordings (three consecutive days/week) were taken at 50 and 60 weeks. At 60 weeks, three hens/pen were euthanized for brain and cecal microbiota collection. Threatening, fighting, head, body, and feather pecking all occurred less frequently at 60 weeks in the SYN group (p < 0.05). Plasma corticosterone, adrenocorticotropic hormone, dopamine, and serotonin were significantly lower while tryptophan and 5-hydroxyindoleacetic acid were significantly higher in birds from the SYN group (p < 0.05). Significant differences in serotonin, 5-hydroxyindoleacetic acid, dopamine, homovanillic acid, and 3,4-dihydroxyphenylacetic acid were observed in the hypothalamus, hippocampus, and amygdala of the brain. Serotonin and dopamine turnover rates were significantly different in all three regions of the brain (p < 0.05). Cecal counts of Lactobacillus and Bifidobacterium were significantly higher in the SYN group (p < 0.05). Synbiotic supplementation resulted in many significant differences, indicating activation of the serotonergic systems and modulation of both the MGB axis and HPA axis with positive effects on welfare and stress. Full article

Injurious behaviors (i.e., aggressive pecking, feather pecking, and cannibalism) in laying hens are a critical issue facing the egg industry due to increased social stress and related health and welfare issues as well as economic losses. In humans, stress-induced dysbiosis increases gut permeability, releasing various neuroactive factors, causing neuroinflammation and related neuropsychiatric disorders via the microbiota–gut–brain axis, and consequently increasing the frequency and intensity of aggression and violent behaviors. Restoration of the imbalanced gut microbial composition has become a novel treatment strategy for mental illnesses, such as depression, anxiety, bipolar disorder, schizophrenia, impulsivity, and compulsivity. A similar function of modulating gut microbial composition following stress challenge may be present in egg-laying chickens. The avian cecum, as a multi-purpose organ, has the greatest bacterial biodiversity (bacterial diversity, richness, and species composition) along the gastrointestinal tract, with vitally important functions in maintaining physiological and behavioral homeostasis, especially during the periods of stress. To identify the effects of the gut microbiome on injurious behaviors in egg-laying chickens, we have designed and tested the effects of transferring cecal contents from two divergently selected inbred chicken lines on social stress and stress-related injurious behaviors in recipient chicks of a commercial layer strain. This article reports the outcomes from a multi-year study on the modification of gut microbiota composition to reduce injurious behaviors in egg-laying chickens. An important discovery of this corpus of experiments is that injurious behaviors in chickens can be reduced or inhibited through modifying the gut microbiota composition and brain serotonergic activities via the gut–brain axis, without donor-recipient genetic effects. Full article

The objective of this on-farm study was to determine if flocks showing feather damage and/or cannibalism would have a higher fear response to the novel object (NOT) and the association between different housing and welfare parameters on results of the NOT. Therefore, 16 flocks were observed during the laying period in Germany. In total, there were six barns, seven free-range, and three organic flocks. The plumage and integument condition of 50 birds of each flock were evaluated at 4 different times during the laying period (V1: 18th to 23rd week of life, V2: 26th to 35th week of life, V3: 49th to 57th week of life, V4: 61st to 73rd week of life). At the same observation times, the NOT was performed in the flocks (at four different locations per visit time). Based on the average number of hens gathered around the novel object (NO) within the period of two minutes, conclusions can be made about the fearfulness of the flock. The present study shows that the more fearful a flock was, the more frequent feather damage (p < 0.001) and cannibalism (p < 0.01) occurred. Age and flock size were associated with fearfulness. Fearfulness of hens increased with the increasing age of hens (p < 0.001) and with an increasing flock size (p < 0.001). Hens of white feather color appeared to be more fearful than brown hens (p < 0.001). Hens kept on barn farms showed significantly lower numbers of hens around the novel object (p < 0.001) than on free-range farms, which possibly indicates that having permanent access to outdoor space generally appears to be associated with the fearfulness of a flock. Full article