Feather Pecking Research Articles

Study of extended homozygous chromosome regions in Italian partridge breed of chickens

Selection and accompanying inbreeding are the basis for breeding chicken breeds. With the advent of modern molecular methods for assessing inbreeding, it has become possible to identify genes and their functions in the homozygous regions (ROH) of chicken chromosomes. In this study, a genome-wide analysis of homozygous regions of chromosomes in Italian partridge chickens was carried out using an SNP chip Illumina Chicken 60KSNPiSelectBeadChipchip. An average of 177 ± 5 ROH-sequences per chicken were identified in the chicken chromosomes, and the average inbreeding coefficient was 0.30 ± 0.01. It was determined that the chicken genome is dominated by short ROH-sequences of 0.25–2 Mbp. ROH-sequences longer than 8 Mbp indicating recent inbreeding account for no more than 2.2%. It was found that, in general, ROH-sequences are more densely distributed in chicken microchromosomes, with the exception of chromosome 16, which does not have ROH-sequences. This fact is due to the heterozygosity of the alleles of the genes responsible for immunity, located in microchromosome 16. ROH-islands were found in the chicken chromosomes 1, 5, and 14. The genes in ROH-islands are responsible for feather pecking in chickens (DMD gene), immune status (TAB3, EIF2S3 genes), body weight (IL1RAPL1 gene), pH of meat (EIF2S3, APOO, KLHL15 genes), egg production (APOO gene), feed uptake (SAT1 gene), aggressiveness of roosters (SLITRK6 gene), transport of intracellular components in developing neurons and protection of heterochromatin in the cell nuclei of neurons (NDE1 gene), adaptation of chickens to tropical living conditions (CDIN1 gene). Thus, ROH analysis allowed us to identify genes potentially selectable as a result of breeding Italian partridge breed chickens.

Live black soldier fly larvae as environmental enrichment for native chickens: implications for bird performance, welfare, and excreta microbiota

Dietary live insect larvae were recently proposed for use in laying hens and broiler−intensive chicken farming as an innovative form of environmental enrichment, but their use in native dual-purpose chickens has never been investigated. This study aims to evaluate the effects of live black soldier fly (BSF) larvae as environmental enrichment in two autochthonous dual-purpose chicken breeds, namely Bionda Piemontese (BP) and Bianca di Saluzzo (BS), in terms of bird performance, behaviour, integument status, excreta corticosterone metabolites (ECMs), and microbiota analyses. A total of 90 BP and 90 BS hens aged 308 days old were randomly distributed between two treatment groups (three replicates/group/breed, 15 hens/replicate). For the following 90 days, the control group (C) was fed a commercial feed only, whereas the BSF group was fed the commercial diet plus BSF live larvae calculated at 6% of the expected daily feed intake (DFI). Larva ingestion time, bird performance, integument scores, and behavioural observations were assessed at regular intervals, and excreta samples were collected to evaluate ECM and microbiota. The larva ingestion time became faster over the course of the experimental trial (P < 0.001). The DFI of BSF-fed hens was lower than that of C hens independently of breed (P < 0.001), whereas only in the BS hens, the live weight of the BSF-fed group was greater than that of the C group (P < 0.01). The BSF-fed BP hens showed a higher laying rate and feed conversion ratio compared with BSF-BS (P < 0.05). Better total integument scores were observed in BSF-fed BP hens compared with C-birds (P < 0.05). The BSF-fed hens displayed higher frequencies of preening, trotting, and wing flapping than C, as well as a lower incidence of severe feather pecking (P < 0.05). An increase in allopreening was only identified in BSF-fed BS hens with respect to the C hens (P < 0.001). No differences in ECM and faecal microbiota were observed between treatment groups. In conclusion, the administration of BSF live larvae as environmental enrichment has the potential to positively influence the welfare of both BP and BS chickens, by enhancing the frequency of positive behaviours whilst reducing severe feather pecking, without affecting their excreta microbiota. BSF larva administration also has the potential to improve the productive performance and the plumage status of the BP breed.

FCS-Net: Feather condition scoring of broilers based on dense feature fusion of RGB and thermal infrared images

Assessing the feather condition of broilers is crucial for monitoring the animal welfare status and detecting the occurrence of feather pecking activities. Currently, the feather condition of individual broilers is manually scored by trained experts. To provide a more objective and efficient tool for feather condition scoring, a novel deep learning-based model, named Feather Condition Scoring Network (FCS-Net), was proposed based on RGB and thermal infrared images. The FCS-Net model combined the ResNet18 architecture with the proposed Dense Feature Fusion (DFF) module, which can effectively learn the feature mapping relationship between RGB and thermal infrared images. Before inputting the images into the network, an image registration process was conducted to align the RGB and thermal infrared images. The results showed that the FCS-Net model had a good performance for feather condition scoring, with the Accuracy of 97.02%, the Precision of 96.99%, the Recall of 97.04%, the F1 of 97.01%, and the Inference speed of 15.34 fps. Compared to the ResNet18_RGB model, which only utilise RGB images, the FCS-Net model showed notable improvements in Accuracy by 4.02%, Precision by 3.90%, Recall by 4.08%, and F1 by 4.01%. Moreover, it was observed that the FCS-Net model focused more on the back region of the broilers through heatmap visualization. Furthermore, the algorithm was compared with six typical image recognition algorithms including VGG16, ResNet18, SE-ResNet18, DenseNet121, Mobilenet_V2, and Shufflenet_V2_x1_0, as well as the state-of-the-art (SOTA) feather condition assessment methods. The results showed that the FCS-Net model achieved better performance than the six algorithms and the SOTA feather condition assessment methods. This study provided a valuable reference for automated monitoring of feather condition scoring of broilers in smart farming.

The Influence of Cecal Microbiota Transplantation on Chicken Injurious Behavior: Perspective in Human Neuropsychiatric Research.

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.

Effect of different LED light colors on welfare, performance, some behavioral patterns, and blood parameters of Muscovy ducks

BackgroundThe current study was conducted to assess the impact of different LED light colors on welfare indicators in Muscovy ducks. These welfare parameters encompassed growth performance, specific behaviors, tonic immobility (TI), feather score, haematological, and serum biochemical parameters. Eighty-four healthy unsexed Muscovy ducklings aged two weeks were randomly assigned to four groups (3replicates/group; each replicate contains 7 birds) based on different LED light colors. The first group was raised under white light, the second under red light, the third under blue light, and the fourth under yellow light. To assess the impact of various LED light colors on welfare, growth performance indicators (body weight, body weight gain, feed intake, and feed conversion ratio) were measured. Behavioral patterns including feeding, drinking, standing, walking, sitting, feather pecking, and other activities were recorded. Tonic immobility test (TI) and feather condition scoring were conducted at 3, 6, and 10 weeks of age. At the end of the study blood samples were collected for hematological and serum biochemical analyses.ResultsThe results revealed that using blue, yellow, and red colors had no adverse effect on the final body weight of the ducks (P > 0.05). Unlike to red light, blue light significantly reduced feather pecking, TI time and cortisol concentrations and improved the feather condition score (P ≤ 0.05).ConclusionsThe current findings suggest that the application of blue light effectively improves welfare indices and has no detrimental impact on the growth performance of Muscovy ducks thereby positively contributing to their welfare.

Impact of different range areas on behavior, welfare, and performance of Naked Neck chickens.

This study aimed to evaluate the effect of different environmental enrichment tools on behavior, welfare, productive performance, and egg quality traits of Naked Neck chickens. A total of 1080 Naked Neck female chickens (30 weeks old) were used in the present study. A completely randomized experimental design, with 3 treatments having 4 replicates of 90 birds each, was applied. Treatments consisted of 3 different range areas A (121.9 m2), B (152.4 m2), and C (190.5 m2). Behavior (walking, feeding/foraging, sitting, aggressiveness wing flapping, perching, dust bathing, and range use), welfare (foot pad dermatitis, lameness, gait score, and feather pecking), productive performance (egg weight, egg production %, egg mass, and feed intake), egg quality traits (morphometry, egg weight, shell, albumen, and yolk characteristics) were evaluated. There was no influence (P > 0.05) of different range area on bird's behavior, and egg quality traits except walking and rang usage. The range area C promoted productive performance including egg weight, egg production %, egg mass and feed intake, but it did not influence welfare traits. It might be concluded that Naked Neck chicken when reared in free range with different range enrichments did not reveal any difference regarding behavioral parameters, egg morphometry, and egg quality traits. The range area within minimum length and effectively used environmental enrichments (perching and dust bathing area) should be used for backyard poultry to obtain ideal performance.

The Influence of Dietary Synbiotic on Agonistic Behavior, Stress, and Brain Monoamines via Modulation of the Microbiota–Gut–Brain Axis in Laying Hens

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 &lt; 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 &lt; 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 &lt; 0.05). Cecal counts of Lactobacillus and Bifidobacterium were significantly higher in the SYN group (p &lt; 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.

3 The impact of early-life cecal microbiota transplantation on injurious behaviors in egg-laying chickens

Abstract Injurious behaviors in laying hens are a critical issue facing the poultry egg industry. Recent studies have shown that the gut microbiota influences host brain function and behavioral characteristics in humans and various animals. In laying hens, it has been reported that injurious behaviors (such as aggression, feather pecking and cannibalism) are associated with dysregulation of the microbiota-gut-brain axis. To further interrogate the role of the microbiota-gut-brain axis on bird behavior, we used two inbred layer chicken lines, 63 and 72 (line 72 displays more aggressive behavior), and transferred pooled cecal contents from either line to day of hatch chicks. Cecal microbiota transplantation (CMT) from each line was conducted once daily, by gavage, from d 1 to 10, then boosted once weekly from wk 3 to 5. We hypothesized that the cecal microbiota composition and animal behavior in recipient birds would be similar to that of their donor animals because of the microbiota-gut-brain axis. Microbial communities were compared using 16S rRNA gene amplicon sequencing, behavior was recorded in home cages as well as in paired aggression tests, and physiological measurements were taken from brain tissue and blood to measure levels of neurotransmitters and immune function. When examining the differences in the donor birds, hypothalamic serotonin and tryptophan concentrations were greater for line 63 compared with line 72 birds (P &amp;lt; 0.05). Plasma corticosterone, heterophil/lymphocyte ratios, and central norepinephrine concentrations were less for line 63 birds (P &amp;lt; 0.05). Cecal microbial diversity was not statistically different between the lines, but many bacterial taxa were differentially abundant between the two lines. After cecal transplantation, 63-CMT (recipient) birds displayed less aggressive behavior with a greater hypothalamic serotonergic activity at wk 5, similar to donor birds. Correspondingly, two amplicon sequence variants (ASVs) belonging to Lachnospiraceae and one Ruminococcaceae UCG-005 ASV were positively correlated with the concentrations of brain tryptophan and serotonin, respectively. Along with greater aggression, 72-CMT birds seemed to have greater physical growth traits (increased body weight, ileal villus/crypt; P ≤ 0.05), but decreased concentrations of brain norepinephrine and dopamine, and the greatest ileal serotonin turnover in the ileum at wk 5 (P &amp;lt; 0.05). ASVs belonging to Mollicutes RF39 and GCA-900066225 in 72-CMT birds were negatively correlated with the brain 5-hydroxyindoleacetic acid (5-HIAA) at wk 5, and one Bacteroides ASV was negatively correlated with plasma serotonin at wk 16. Meanwhile, 63-CMT birds potentially had better gut health and immune function (greater concentrations of ileal mucosal secretory IgA, plasma IL-10; P &amp;lt; 0.05). These results suggest linkages among serotonergic activity, stress response, innate immunity, and gut microbiota populations and that CMT could be a novel strategy for reducing aggressive behavior through regulating signaling along the microbiota-gut-brain axis.

On‐farm evaluations of animal welfare indicators in laying hens housed with and without environmental enrichment

AbstractIn laying hen husbandry, severe feather pecking and cannibalism are multifactorial problems. Solving these problems is a matter of urgency, as beak trimming is banned in several European countries, including Germany. One approach to addressing severe feather pecking and cannibalism is the administration of additional enrichment material to support normal behaviour. In this on‐farm study, two flocks of 17,500 Lohmann Brown‐Lite laying hens each were evaluated during one production period (18–78 weeks of life, WoL). One flock was provided with alfalfa bales and pecking stones in combination (EnGr), whereas the other flock served as a control without additional enrichment material (CoGr). During production, the flocks were visited at regular intervals. On each visit, a sample of 50 hens per flock were weighed and scored for plumage condition and skin lesions. The mortality rate was recorded daily by the farm staff. No significant difference in plumage condition and mortality rate was found between EnGr and CoGr (p &gt; .05, Mann‐Whitney U test). As there were hardly any skin lesions in both groups during the study period, the effect of additional enrichment material on this variable could not be determined. The average body weight of the EnGr was significantly higher than the average body weight of the CoGr on numerous examination days (26 WoL, p &lt; .001; 34 WoL, p = .040; 42 WoL, p = .007; 62 WoL, p = .041; 66 WoL, p = .006; 74 WoL, p = .036; 78 WoL, p = .028, t‐tests). However, this effect could not be clearly attributed to the administering of additional enrichment material, as the feeding and performance variables for EnGr and CoGr had been recorded together because of the housing for the two flocks being supplied by one silo and water source, and eggs from the flocks being collected altogether.

Do flickering lights impact turkey hen behavior, stress, and fear?

Little is known about the effect of light-flicker frequency on poultry, particularly on turkeys. This experiment examined the impact of light-flicker frequency on the behavior, stress, and fear response of Nicholas Select turkey hens reared to 11 wk. The experiment was a randomized complete block design (2 trials), with a one-way factorial analysis evaluating 3 light-flicker frequencies (30, 90, or 195 Hertz; Hz). Birds (n = 3,276 per trial) were housed in 9 individual environmentally controlled rooms (3 replicates per treatment per trial). Data collected included: behavior (4, 8, and 10 wk), incidence of aggressive damage, heterophil-to-lymphocyte ratio, and novel object test (daily d 1-7 and at 4, 8, and 11 wk). Data were analyzed using Proc Mixed (SAS 9.4), with significance declared at P ≤ 0.05. Behavior data are presented as the percentage of time spent performing the behavior. At 4 wk, gentle feather pecking and exploratory behaviors were higher under 195 Hz compared to 30 Hz (P = 0.04 and P = 0.05, respectively). Preening was higher under 90 Hz compared to 30 Hz (P = 0.05). At 8 wk, wing flapping was lowest under 195 Hz (P < 0.01). Gentle feather pecking was higher under 90 and 195 Hz compared to 30 Hz (P = 0.02). Fighting (P = 0.05), aggressive pecking (P = 0.02), and aggressive behaviors (P = 0.01) were lower under 30 Hz compared to 90 Hz. At 10 wk, preening was decreased under 30 Hz (P = 0.03). Incidences of aggressive damage were reduced under 30 Hz compared to 90 Hz (0 d-4 wk; P = 0.01) and under 30 compared to both 90 and 195 Hz (4-8 wk; P = 0.01). At 11 wk, heterophil-to-lymphocyte ratios were lowest under 30 Hz (P = 0.04). The novel object test was unaffected by flicker treatment. In conclusion, many behaviors and the stress and fear responses were unaffected by either visible or non-visible flicker. However, visible flicker (30 Hz) reduced some comfort and exploratory behaviors early in life, and the impact on preening continued to older ages, suggesting minor negative impacts of flicker, particularly early in life.

Research note: Expert opinions of feather sucking and licking behavior in meat chicken breeder birds

Feather sucking, or feather licking, has been reported anecdotally by employees in the Australian meat chicken breeder industry, but scarcely in the scientific literature. Consequently, the causes and implications of this behavior in meat chicken breeding chickens is relatively unknown. We surveyed 17 industry experts to generate hypotheses about feather sucking behavior. We aimed to understand the frequency and when it occurs, and attempted to understand what may cause an ‘outbreak’. The recruitment of participants was intentionally biased towards Australian perspectives; only 5 of the 17 participants were international. All participants, except 1, had seen feather sucking/licking behavior (94.1%) and most participants (80%) suggested that the behavior was most frequently observed during rearing. Participants presented varying concerns about this behavior, ranging from the perspective that it was ‘normal’ and had no impact on welfare, to concerns about mating injuries due to damaged feathers, increased risk of feather pecking and cannibalism, and psychological stress indicated by expression of repetitive (seemingly) functionless behavior. ‘Feather licking’, ‘feather sucking’, ‘feather eating’, and ‘feather pecking’ were terms used interchangeably, leading to confusion by participants about the cause and implications of the target behavior. The most common factors reported as the cause were boredom (52.9%), nutritional deficiencies (47.1%), and feed restriction (41.2%) and more than 80% of respondents agreed that stress contributes to feather sucking. The outputs from this study reflect only a small, but expert, number of opinions on feather sucking/licking behaviors in the Australian meat chicken breeder industry. A systematic understanding of this behavior is needed to provide insight into causation and the implications for welfare.

Research Note: Effects of environmental sound stimulus on behavioral responses, cortisol levels, and horizontal immunity of transferred pullets

The aim of this study was to investigate the effects of prolonged exposure to varying levels of music or noise on the behavioral, physiological, and immune responses of pullets following their transfer to an egg-laying facility. A total of 240 one-day-old Hy-Line Brown pullets were randomly assigned to five groups: 0 dB sound stimulation, low-decibel music (65-75 dB), high-decibel music (85-95 dB), low-decibel noise (65-75 dB), and high-decibel noise (85-95 dB) stimuli. Pullets received music or noise stimuli 10 h per d from 1-day-old to 16-wk-old and were then transferred to the egg-laying facility. The results indicated that feeding and drinking behaviors significantly decreased (P < 0.05), whereas feather pecking, aggression, and preening behaviors significantly increased (P < 0.05) in the pullets after transfer. Pullets also had higher serum cortisol (COR) levels (P < 0.05), whereas immunoglobulin Y (IgY), tumor necrosis factor-α (TNF-α), interferon-γ (INF-γ), interleukin-1β (IL-1β), interleukin-2 (IL-2) and interleukin-6 (IL-6) levels significantly increased (P < 0.05). Low-decibel sound stimuli increased aggressive behavior and decreased pecking behavior (P < 0.05). High-decibel sound stimuli decreased feather pecking, cage pecking, aggression, and sham dustbathing behaviors (P < 0.05). In addition, a low-decibel sound stimulus decreased the serum COR content, and increased the serum IL-6 level in the transferred pullets. A high-decibel sound stimulus also induced shorter tonic immobility (TI) durations in pullets on d 7 after transport stress. Meanwhile, high-decibel sound stimulus decreased the serum IL-6 and TNF-α levels of pullets. In conclusion, the transfer has detrimental effects on the pullets. Long-term sound stimulation effectively mitigated the negative impact of transportation stress on pullets. Among them, the high-decibel sound stimulus showed more promise in relieving transport stress.

Karakterisasi Ekson 4 Gen DRD4 pada Ayam Arab Tiara G15 dengan Tingkah Laku Feather Pecking

Feather pecking (FP) is a potentially fatal behavioral disorder in chickens. Various factors, including genetics such as DRD4 gene, affected this behavior. The Arab TIARA G15 chicken is a laying hen breed selected based on FP behavior. However, genetic selection linked to this FP as not yet been conducted. This study aimed to characterize the 4th exon of the DRD4 gene in Arab golden red TIARA G15 chickens and confirm its potential as an FP genetic marker. The study used 30 TIARA G15 chickens that were divided into three groups: high feather pecking (HFP) (n = 10), low feather pecking (LFP) (n = 10), and control (n = 10). The DNA extraction kit extracted total genomic DNA from each blood sample. The 4th exon of the DRD4 gene was amplified using primer pairs MU140-141. Amplicons from samples within a group were pooled in a single tube and sequenced using the Sanger method. The sequencing results were analyzed for nucleotide variation using MEGA6 software. Nucleotide sequences obtained from each group were 642 bp, consisting of partial intron 3 (55 bp), full-length exon 4 (202 bp), and partial 3'UTR (385 bp). None of the three groups of Arab golden red TIARA G15 chickens were found to have any nucleotide variants in the partial intron 3, full-length exon 4, and 3'UTR regions of the DRD4 gene. Consequently, selecting the full-length exon 4 of the DRD4 gene for FP behavior was not feasible. Keywords: arab chicken, DRD4, feather pecking, golden red

Preening cups in duck housing are associated with an increase in central dopamine activity that suggests a negative affective state

Preening cups are a form of environmental enrichment that provides Pekin ducks a semi-open water source to express their natural behaviors. We recently observed that preening cups may increase feather pecking behaviors in ducks. Thus, we set out to determine if this form of enrichment can impact the affective state of Pekin ducks. To accomplish this goal, we evaluated the effect of preening cups on serotonin (5-HT) and dopamine (DA) turnover via mass spectrometry and their respective synthetic enzyme gene expression via qRT-PCR. Our study investigated the link between aggressive pecking with levels and activity of brain 5-HT and DA. Brain 5-HT and DA levels and activity have been established for decades to be associated with affective states. Grow-out Pekin ducks (n = 260) were housed at Purdue and raised per industry standards. On day 18, brains were collected from ducks in pens before preening cups were placed (PRE, n = 6) and, again on day 43, in pens with (PC, n = 6) and without (CON, n = 6) preening cups. Brains were dissected into right and left halves, then further microdissected into 4 brain areas: caudal mesencephalon (CM), rostral mesencephalon (RM), diencephalon (DI), and forebrain (FB). The right hemisphere was used for mass spectrometry to determine the neurotransmitter concentration (ng/mg of tissue) and those concentrations were applied to neurotransmitter turnover equations. There were no differences across treatments for 5-HT turnover in any brain area. There were differences in DA turnover across age (P = 0.0067) in the CM and across treatments (P = 0.003) in the RM. The left hemisphere of the brain was used to perform qRT-PCR on the genes of 5-HT and DA production enzymes. Within the CM, day 43 duck brains had increased (P = 0.022) tryptophan hydroxylase and tyrosine hydroxylase relative mRNA levels. All other brain areas showed no differences. Our data suggest that ducks housed with preening cups and that showed increased feather pecking are associated with increased brain DA activity. The increased DA in the brain may lead to a predisposition for increased aggression in the form of feather pecking.

The Impact of Early-Life Cecal Microbiota Transplantation on Social Stress and Injurious Behaviors in Egg-Laying Chickens.

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.

Resource choice during ontogeny enhances both the short- and longer-term welfare of laying hen pullets

We hypothesised that resource choice during early life contributes to both current and longer-term beneficial effects on animal welfare. We investigated this hypothesis in a longitudinal cross-over experiment with laying hen pullets (Gallus gallus domesticus) reared in pens with one or four litter and perch types, respectively (n = 8 pens/treatment, all providing ample and identical litter and perch space). After 4 weeks (chick period), half the pens were modified to provide the opposite treatment (juvenile period). After 11 more weeks, all groups were moved to novel, identical laying pens (adult period; Week 16–27). In support of our hypothesis, the opportunity to choose between multiple litter and perch variants was associated with higher levels of positively-valenced behaviours, including play as chicks and dustbathing as juveniles and adults, and lower levels of negatively-valenced behaviours, including feather pecking as chicks and juveniles and aggressive pecking as adults. Resource choice in the juvenile period also led to better juvenile and adult plumage condition, and greater growth as adults. We conclude that the opportunity to choose among different litter and perch types, instead of having only one type of each, had both short- and longer-term positive effects on the birds’ affective states and physical condition.

Why the caged bird sings: Rethinking the Anthropocene with Gallus gallus

Previous research argues Gallus gallus (chickens) makes a strong candidate for a chrono-stratigraphic signal of the Anthropocene, but the history of how G. gallus came to mark the Anthropocene remains to be told. At the macro-level, G. gallus tells a story of slavery, sexism, scientific progress, settler colonialism, nation building, socialist welfare programs, capitalist expansionism, and plantation agriculture. At the micro-level, G. gallus tells a story of the suffering of crippling growth rates and confinement as well as the agency of metabolic labor; goal-directed behavior of hunger, thirst and survival; and resistance in the form of efforts at escape and violence of feather pecking. This paper tells a history that recognizes the sensorial worlds and intentionality of G. gallus, and demonstrates how G. gallus is one instantiation of an assemblage of species that were co-opted into a system that partially overlaps with and simultaneously sustains and threatens the technosphere.

The effects of stocking density on growth, morphological development, behavior, and welfare parameters in pheasants (Phasianus colchicus).

In pheasants, which are generally raised in large flocks, stocking density is important for their growth and development, normal behavior and welfare. But there is still a lack of information on the optimum stocking density for game birds. This research was conducted on a total of 200 pheasants to examine the effects of low (5 pheasant/m2) and high (10 pheasant/m2) stocking density rearing practices on body weight, morphological development, behavioral characteristics and welfare parameters such as foot-pad dermatitis and plumage quality. When we look at the study results, it was determined that the density of stocking did not make a difference in the first 13 weeks of age, but pheasants reared at low density at the ages of 14-16 weeks reached higher body weight. In terms of body weight at 14, 15, and 16 weeks, the low stocking density group had an average of approximately 41, 71, and 94 g higher than the high stocking density group, respectively (p<0.05). It had been found that low density provides better morphological development. The low group was found to be significantly higher than the high group in terms of ornithological size, wingspan, back length, tail length, head length and head width, 5.9 cm, 2 cm, 1.3 cm, 7.6 cm, 1.7 mm and 1 mm, respectively (p<0.05). Since the animals in the low group had more individual space, they had the opportunity to perch and therefore exhibit more passive behavior. On the other hand, pheasants in the low group exhibited higher levels of aggressive behavior (p<0.05). More foraging behavior was observed in the higher group and the low-density group consumed more feed in the 14th week (p<0.05). But no significant differences were detected between groups in terms of feed consumption in other weeks (p>0.05). A 1.12 point higher score was calculated in the low group compared to the high group, especially in terms of tail feather quality, and as a result, pheasants reared in low stocking density had better plumage quality (p<0.05). It had been determined that as the stocking density decreases in the rearing of pheasants, they exhibit easier flight and roosting behaviors and therefore they were less affected by feather pecking behavior and had better feather quality. In addition, it had been determined that pheasants grow and develop better in this group, which had more rest opportunities. In conclusion, rearing at low stocking density is recommended for better fattening performance and better welfare conditions.

Towards genetic improvement of social behaviours in livestock using large-scale sensor data: data simulation and genetic analysis

BackgroundHarmful social behaviours, such as injurious feather pecking in poultry and tail biting in swine, reduce animal welfare and production efficiency. While these behaviours are heritable, selective breeding is still limited due to a lack of individual phenotyping methods for large groups and proper genetic models. In the near future, large-scale longitudinal data on social behaviours will become available, e.g. through computer vision techniques, and appropriate genetic models will be needed to analyse such data. In this paper, we investigated prospects for genetic improvement of social traits recorded in large groups by (1) developing models to simulate and analyse large-scale longitudinal data on social behaviours, and (2) investigating required sample sizes to obtain reasonable accuracies of estimated genetic parameters and breeding values (EBV).ResultsLatent traits were defined as representing tendencies of individuals to be engaged in social interactions by distinguishing between performer and recipient effects. Animal movement was assumed random and without genetic variation, and performer and recipient interaction effects were assumed constant over time. Based on the literature, observed-scale heritabilities ({h}_{o}^{2}) of performer and recipient effects were both set to 0.05, 0.1, or 0.2, and the genetic correlation ({r}_{A}) between those effects was set to – 0.5, 0, or 0.5. Using agent-based modelling, we simulated ~ 200,000 interactions for 2000 animals (~ 1000 interactions per animal) with a half-sib family structure. Variance components and breeding values were estimated with a general linear mixed model. The estimated genetic parameters did not differ significantly from the true values. When all individuals and interactions were included in the analysis, the accuracy of EBV was 0.61, 0.70, and 0.76 for {h}_{o}^{2} = 0.05, 0.1, and 0.2, respectively (for {r}_{A}= 0). Including 2000 individuals each with only ~ 100 interactions, already yielded promising accuracies of 0.47, 0.60, and 0.71 for {h}_{o}^{2} = 0.05, 0.1, and 0.2, respectively (with {r}_{A} = 0). Similar results were found with {r}_{A} of – 0.5 or 0.5.ConclusionsWe developed models to simulate and genetically analyse social behaviours for animals that are kept in large groups, anticipating the availability of large-scale longitudinal data in the near future. We obtained promising accuracies of EBV with ~ 100 interactions per individual, which would correspond to a few weeks of recording. Therefore, we conclude that animal breeding can be a promising strategy to improve social behaviours in livestock.

Preening cups increase apparent wet preening behaviors, but have no impact on other behaviors, body condition, growth, or body morphometrics of grow-out Pekin ducks

Preening cups may be a form of open water that would allow ducks to express preening behaviors. We set out to test the hypothesis that preening cups would not have detrimental effects on ducks or their environment. Control pens (N=6, 65 ducks/pen) had nipple lines while experimental pens (N=6, 65 ducks/pen) had the same nipple line plus one preening cup (PC). Body weights of 30 ducks per pen, and body condition scores on 50 ducks per pen were recorded weekly. On d 18 and 43, 5 ducks per pen were euthanized and their spleens, Bursas, liver, and uropygial glands were weighed. Behavior data were collected using scan sampling with video being recorded for 72 continuous hours at 4 different ages: 25 d, 30 d, 36 d, and 40 d. Body morphometrics were analyzed by 2-way ANOVA with repeated measures. Body condition scoring was analyzed by Pearson's chi-square. The GLIMMIX procedure (SAS 9.4) was used for behavioral analyses to examine treatment differences in the proportion of ducks performing dry preening, wet preening, eating, drinking, standing, and laying down. Feather pecking, feather picking, preening conspecifics (also known as allopreening), dunking head, and drinking from preening cup were analyzed using PROC LOGISTIC with the Firth bias correction for quasi-complete separation and odds ratios were calculated. More PC ducks housed with PC performed wet preening compared to control ducks (25 d: F1,26=6.90, P=0.0143; 30, 36, and 40 d; F1,78=24.53, P < 0.0001). Ducks in the PC group were also more likely to lay down compared to controls (25 d: F1,33=4.95, P=0.0330). No differences were observed for any other behavior, body condition score, body weight or morphometrics at any age. Although ducks in the preening cup group showed an increase in wet preening, our data suggest that open water is not necessary to maintain feather condition or uropygial gland size.