Cannibalistic Pecking Research Articles

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.

Types and clinical presentation of damaging behaviour - feather pecking and cannibalism in birds

Behavioural disorders, including feather pecking and cannibalism, are a common problem in both domestic and wild birds. The consequences of this behaviour on welfare of birds incur serious economic losses. Pecking behaviour in birds is either normal or injurious. The type of normal pecking behaviour includes non-aggressive feather pecking – allopreening and autopreening. Aggressive feather pecking aimed at maintenance and establishment of hierarchy in the flock is not associated to feathering damage. Injurious pecking causes damage of individual feathers and of feathering as a whole. Two clinical presentations of feather pecking are known in birds. The gentle feather pecking causes minimum damage; it is further divided into normal and stereotyped with bouts; it could however evolve into severe feather pecking manifested with severe pecking, pulling and removal, even consumption of feathers of the victim, which experiences pain. Severe feather pecking results in bleeding from feather follicle, deterioration of plumage and appearance of denuded areas on victim’s body. Prolonged feather pecking leads to tissue damage and consequently, cannibalism. The nume­rous clinical presentations of the latter include pecking of the back, abdomen, neck and wings. Vent pecking and abdominal pecking incur important losses especially during egg-laying. In young birds, pulling and pecking of toes of legs is encountered. All forms of cannibalistic pecking increase morta­lity rates in birds. Transition of various pecking types from one into another could be seen, while the difference between gentle, severe feather pecking and cannibalism is not always distinct.

The role of genes, epigenetics and ontogeny in behavioural development

This review focuses on the role of genes, epigenetics and ontogeny in behavioural development of animals. The behavioural characteristics of an individual are determined by its genes and by its physical and social environment. Not only the individual's early life and current environment are of importance, but also the environment of previous generations. Through epigenetic processes, stress in parents and even grandparents can translate into changes in behavioural and physical characteristics of the offspring. Another influential factor for behavioural development is maternal hormones. Recent studies indicate that hormonal effects may also be closely related to epigenetic changes. Also, the environment during ontogeny has considerable impact on behavioural development: in both mice and laying hens, high quality maternal care resulted in animals that were less fearful. In laying hens maternal care also led to a reduction in cannibalistic pecking. Genetic selection and selection experiments will also play a key role in breeding animals for the housing systems of the future. To optimize behavioural development of farm animals and to minimize risks of damaging behaviour, integral approaches are needed that combine selection of the optimal genotype with provision of a favourable environment for parents and offspring, both during ontogeny and later life.

A bespoke management package can reduce levels of injurious pecking in loose-housed laying hen flocks

This study investigated the protective effects of an on-farm management package designed to reduce injurious pecking (IP) in loose-housed laying hens. A systematic review of scientific literature generated 46 potentially...

Production performance and proportion of nest eggs in layer hybrids housed in different designs of furnished cages

The aim of the study was to compare use of nests, production performance, and egg quality in 4 designs of furnished cages (FC) housing 8 (T8), 10 (T10), 20 (T20), or 40 (T40) layers. The FC housing 8 and 10 hens were commonly used in commercial egg production in Sweden, whereas the cages housing 20 and 40 hens constituted new designs, at present not allowed in Sweden. The FC also differed in design and location of litter facilities. The study comprised 2 full production cycles (20-72 wk of age). Trial 1 included 588 Hy-Line White W98 and 460 Hy-Line Brown layers, and trial 2 used 572 Lohmann Selected Leghorn and 588 Lohmann Brown layers. In accordance with Swedish prohibition, beak treatment was not conducted. In both trials production parameters and mortality were considered normal and levels were unaffected by cage design. Deaths attributable to cannibalistic pecking were rare. Overall, exterior egg quality was superior in T8 compared with T20 and T40, whereas T10 generated intermediate results. Genotype differences were found in production performance, exterior egg quality, and use of nests. In T8 and T10 at least 95% of the eggs were laid in nest whereas in T20 and T40 a considerable percentage of eggs were laid on the litter mat, constituting the litter facility in those cage models. Additional lighting of litter mats (trial 2) had no effect on layers' choice of site for egg laying. Dividing T40 cages in 2 identical cage halves by a rear partition with pop holes had no effect on any of the traits measured. In conclusion, housing larger groups of non-beak-treated hens together in FC is possible, with acceptable levels of production and mortality, provided that cannibalism does not develop. The inferior egg quality in T20 and T40, likely caused by the large proportions of misplaced eggs, needs to be considered in the further development of those cage designs.

Breeding amiable animals? Improving farm animal welfare by including social effects in breeding programmes

AbstractSocial interactions between individuals, such as co-operation and competition, are key factors in evolution by natural selection. As a consequence, evolutionary biologists have developed extensive theories to understand the consequences of social interactions for response to natural selection. Current genetic improvement programmes in animal husbandry, in contrast, largely ignore the implications of social interactions for the design of breeding programmes. Recently, we have developed theoretical and empirical tools to quantify the magnitude of heritable social effects, ie the heritable effects that animals have on their group mates’ traits, in livestock populations, and to utilise those effects in genetic improvement programmes. Results in commercial populations of pigs and laying hens indicate large heritable social effects, and the potential to substantially increase responses to selection in traits affected by social interactions. In pigs, including social effects into the breeding programme affected aggressive behaviour, both at mixing and in stable groups, indicating changes in the way dominance relationships are established and in aggressiveness. In laying hens, we applied selection between kin-groups to reduce mortality due to cannibalistic pecking. This resulted in a considerable difference in mortality between the low mortality line and the unselected control line in the first generation (20 vs 30%). Furthermore, changes in behavioural and neurobiological responses to stress were detected in the low mortality line, pointing to reduced fearfulness and stress sensitivity. These first results indicate that including social effects into breeding programmes is a promising way to reduce negative social interactions in farm animals, and possibly to also increase positive social interactions, by breeding animals with better social skills.

Low Dietary Energy Concentration, High Nonstarch Polysaccharide Concentration, and Coarse Particle Sizes of Nonstarch Polysaccharides Affect the Behavior of Feather-Pecking-Prone Laying Hens

An experiment was conducted with 504 non-cage-housed ISA Brown laying hens from 18 to 40 wk of age to investigate the separate effects of dietary energy concentration, nonstarch polysaccharide (NSP) concentration, and particle sizes of added NSP source on the eating behavior, feather-pecking behavior, and hen performance of laying hens. Hens were allotted to 1 of 6 dietary treatments according to a 2 × 3 factorial arrangement, with 7 replicates per treatment. The factors were control and low energy concentration (2,825 vs. 2,540 kcal/kg), control and high NSP concentration (133 vs. 195 g/kg), and fine vs. coarse particle size of the added NSP source in the high-NSP diets. We hypothesized that eating time would be increased by feeding low-energy diets or coarsely ground, high-NSP diets, or both, resulting in reduced feather-pecking behavior, without negatively affecting hen performance. Energy reduction, NSP addition, and coarse grinding of NSP increased eating time by 14.2% (P= 0.001), 17.2% (P< 0.001), and 7.9% (P= 0.075), respectively, compared with the control level of these factors. Addition of NSP decreased eating rate (g/min) by 21.0% (P= 0.010). Layers already performed gentle feather-pecking behavior during the fifth week of the rearing period. Dietary treatments did not affect the maximal level of feather condition scores, but arise of feather damage was delayed by 10 wk in hens fed low-energy, coarsely ground, NSP-rich diets compared with hens fed control diets. Hens fed the control NSP diets showed reduced culling rates, because of less cannibalistic pecking, when energy concentration was decreased (44.1 vs. 13.1%), whereas in the high-NSP diets, culling rate decreased slightly when hens were fed the low-energy diets (31.6 vs. 28.6%; P= 0.071). Hens that were fed the low-energy diets compensated for the 10% reduction in energy concentration by a 9.3% higher maximal feed intake (143.0 vs. 130.8 g/d). Hen performance and BW gain of the hens were not affected by dietary treatments. We concluded that hens that were fed low-energy or high (coarsely ground)-NSP diets spend more time on feed intake, compared with hens that were fed the control diets. As a result, hens in some treatments showed less feather-pecking behavior.

Management and housing systems for layers – effects on welfare and production

Except for conventional cages, the most common housing systems for laying hens comprise deep litter, aviaries and more recently furnished cages. Layers in floor systems may also include out-door keeping. Furnished cages will be the only legal form of cages in the EU from 2012 (1999 EU-directive) but have as yet only been installed in significant numbers in Sweden and partly in Norway, Germany and Great Britain. Climate, feed, bird genotype, group size as well as the legal possibility to beak trim or to use certain medical treatments (mainly against endo- and ectoparasites) or not, are all conditions affecting results with different housing systems in different countries. Offering benefits to the bird as regards increase in behavioural repertoire as well as providing more space, all alternatives to conventional cages, require new or special knowledge of management. This is due to the fact that these systems often include higher potential risks in production and health of layers. This especially applies to non-cage systems (Petermann, 2003). The main issues to control in larger group floor housing are parasitic disorders, outbreak and spreading of cannibalistic pecking, increased feed intake, misplaced eggs, catching of spent hens and air quality (dust and ammonia levels). Many management practices to reduce some of these risks have been presented including rearing method, medication, vaccination, light intensity, genotype, feed composition, beak trimming and - for improved air quality - the use of spraying/fogging with water or oil as well as more frequent manure removal at closer intervals have been practised. Coming in a wide range of models and group sizes, the furnished cages attempt to combine the benefits and reduce the disadvantages of floor keeping and conventional cages. The most developed models of furnished cages provide similar production results to conventional cages. However, differences still exists e.g. in egg quality traits between models. Design and location of nests, perches and litter are all important factors.In conclusion, future trends in investments for housing system in egg production will have to take into account several factors apart from the degree of success from technical development of each system. These will probably involve national directives regarding beak trimming, stocking densities, directives of withdrawal times of medication and occupational safety on one side and national markets and trades for different categories of eggs on the other.

Feather pecking and cannibalism in free-range laying hens as affected by genotype, dietary level of methionine + cystine, light intensity during rearing and age at first access to the range area

An experimental small-scale free-range system was used in the two experiments reported here and consisted of 24 independent units. Experiment 1 was designed to test genotype and level of dietary methionine+cystine. Four genotypes were used: ISA brown (ISA), new hampshire (NH), white leghorn (WL) and a cross between NH and WL (C). In the laying period the content of the essential amino acids methionine+cystine in the food was either low (4.0 g/kg) or high (8.0 g/kg). Experiment 2 was designed to test three genotypes, two levels of light intensity (3 or 10 lx) and early (4 weeks old) versus late (16 weeks old) access to the range area. The genotypes used were ISA, Lohmann selected leghorn (LSL) and Danish landrace (DL). The level of feather pecking was in general low in both experiments. In experiment 1, at 14 weeks, NH-birds gave significantly fewer bouts of feather pecking than ISA and C, while C gave more pecks than NH and WL. In experiment 2, at 11 weeks, ISA gave significantly fewer bouts as well as feather pecks compared to DL and LSL. In experiment 1, the plumage of 98% of ISA-hens, 70% of C-hens, and 31% of NH-hens was damaged at 35 weeks, while none of WL-hens had any damage. Damage to feathers at the back, which mostly results from feather pecking, corresponded well with these figures of general damage. In experiment 2 this was not so. The plumage of 54% of DL, 10% of ISA and 70% of LSL was damaged, but 54, 1 and 1%, respectively, had suffered damage to the back feathers, indicating feather pecking in DL and not in the other genotypes. Age at access to the range and light intensity during rearing did not affect the plumage condition of ISA and LSL at 35 weeks. In experiment 1, mortality from cannibalism was higher in ISA compared to the other genotypes (17.5, 2.4, 0 and 1.1% in ISA, NH, WL and C, respectively). Mortality from impaction (mainly grass) was higher in NH than in ISA and WL. A high and significant, positive correlation (0.60–0.80) was found between feather or skin damage and mortality from cannibalism. Plumage condition recorded at the post mortem examination was worse for hens diagnosed dead from cannibalistic pecking compared to other diagnoses (16.4 versus 19.7 points, P<0.001).

Beak Trimming Benefits Vary Among Egg-Strain Pullets of Different Genetic Stocks ,

The current study examined the effects of three beak treatments and three genetic stocks of White Leghorn pullets on part-year egg production and losses from cannibalistic pecking. Special attention was directed towards the consistency of beak treatment effects over genetic stock. Both beak treatment and genetic stock influenced losses from cannibalistic pecking, and beak treatment by genetic stock interactions were found for several traits. When beaks were intact, two stocks had relatively minor incidences of cannibalism but the third had heavy losses; mean percentages of pullets lost were .7, 2.8, and 18.1, respectively. When beak trimming was carried out once or twice during the rearing period, death losses to 44 wk were so infrequent among all stocks that chi-square analyses were not justified. Inconsistent effects of beak treatment on egg production traits were detected among the three stocks. One stock was not influenced by beak treatment, another benefited somewhat erratically, and the third stock benefited substantially in terms of hen-housed production.

Research Note: Genetic Adaptation to Multiple-Bird Cage Environment is Less Evident with Effective Beak Trimming ,

Selection of hens with intact beaks for high performance in multiple-bird cages has produced a stock that clearly exceeds its unselected control when hens have intact beaks but shows less advantage when comparisons involve effectively beak-trimmed birds. The selected stock performed at about the same level as a stock recently derived from a commercial source (but with two generations of relaxed selection) when birds had intact beaks but at a lower level when birds had their beaks trimmed. Relative incidences of deaths from cannibalistic pecking were partially responsible for the results obtained.

Selection and Beak-Trimming Effects on Behavior, Cannibalism, and Short-Term Production Traits in White Leghorn Pullets ,

Pallets of stocks derived from the North Central Randombred White Leghorn population without selection (C) or selected (S) on family performance when kept with beaks intact in multiple-hen cages were compared. Pullets had intact, one-fourth, or one-half of the beak removed (IN, 1/4R, and 1/2R, respectively). No stock differences were detected for behavior traits or other measures during the rearing period. However, beak-trimmed pullets were more inactive and feeding behavior was depressed in 1/2R pullets 1 wk after beak trimming.At 16 wk, 1/4R pullets' beaks had regrown but 1/2R pullets' beaks continued to be shorter than IN pullets' beaks. No differences in fearfulness were found between genetic stocks or among beak length treatments early in the laying period. Deaths from beak-inflicted injuries accumulated steadily from 18 wk until the study was ended at 40 wk. Cannibalistic deaths occurred less frequently in S as compared with C pullets within each beak treatment. As the amount of beak removal increased, beak-inflicted mortality decreased.The S pullets had earlier sexual maturity, lighter egg weights, and greater hen-housed egg production and egg mass than C pullets, and 1/2R pullets had greater egg production than 1/4R and IN pullets. Genetic stock by age and beak treatment by age interactions were present for hen-housed production and egg mass, and the interactions appeared to result primarily from increased mortality from cannibalistic pecking with increased age.

Beak Trimming Effects on Behavior Patterns, Fearfulness, Feathering, and Mortality Among Three Stocks of White Leghorn Pullets in Cages or Floor Pens ,

White Leghorn pullets of the Y1, Y2, and North Central Randombred (NCR) experimental stocks were used. Half of the birds of each stock had half of the upper and less of the lower mandible removed at 4 wk of age by making a V-shaped cut as viewed from the side (BT), whereas the other half retained their beaks intact (IN). Pullets were moved from growing pens to a layer house at 18 wk of age. Seventy-two cages and 30 floor pens were filled with 6 and 20 birds per unit, respectively. Pullets within a cage or floor pen were all of the same genetic stock and beak treatment. All measurements were performed within 10 wk after housing, except for mortality in cages.When kept in cages, genetic stocks did not show behavioral differences. However, in floor pens, stock differences were detected in feeding, crouching, and nonaggressive pecking. When kept in cages, the stocks also differed in 24-wk body weight, weight gain from 18 to 24 wk, and certain measures of fearfulness in both cages and pens, and in feather condition at 21 and 22 wk. Mortality from cannibalism and hen-days survival of caged IN pullets differed among genetic stocks. Mortality from cannibalism was absent among pullets kept in experimental floor pens.In cages, BT pullets were less active, gained less weight, and had lower incidence of cannibalism than IN pullets. Also, BT pullets were less nervous and had better feather condition than IN pullets. However, trimming beaks to prevent cannibalism was less effective in NCR pullets than in Y1 or Y2 pullets.In floor pens, BT pullets showed less activity and reduced feeding frequency and less fearfulness as indicated by duration of induced tonic immobility. Agonistic behaviors were not different between BT and IN pullets.From these results, beak trimming could be interpreted as having either stressful or stress-alleviating effects, depending on the criteria used. However, proper beak trimming appears beneficial when cannibalistic pecking is likely to be a problem. The relative benefits of beak trimming vary among genetic stocks.

Beak trimming and genetic stock effects on behavior and mortality from cannibalism in White Leghorn-type pullets

Removal of half of the upper and less of the lower beak of pullet chicks at 4 weeks of age resulted in less pecking at feed, fewer non-agonistic pecks of all kinds, less moving and preening, and more inactive standing and crouching during the following 3 weeks. Escape and avoidance behavior did not differ for 8–9-week-old, intact-beak and trimmed-beak pullets. Body weights, used as indirect indicators of feed intake, were initially suppressed following beak treatment, but trimmed-beak pullets were only marginally lighter by 27 weeks of age. Beak length measures taken 3 months after beak trimming indicated that regrowth had not occurred. Beak trimming was highly beneficial in reducing beak-inflicted feather loss and mortality from cannibalistic pecking in two of three commercial genetic stocks. Pullets of the third stock suffered no greater feather loss when their beaks were left intact than when they were trimmed, and mortality from cannibalistic pecking was essentially absent in this stock, regardless of beak treatment. These results indicate that either no beak trimming or less severe beak trimming is a practical possibility for poultry producers, as soon as appropriate genetic stocks are identified.