Feather pecking is a behavior that occurs most frequently amongst domestic hens reared for egg production,Huber-Eicher, B. and Sebo, F. 2001. The prevalence of feather pecking and development in commercial flocks of laying hens. Applied Animal Behaviour Science, 74: 223–231Sherwin, C.M., Richards, G.J and Nicol, C.J. 2010. A comparison of the welfare of layer hens in four housing systems in the UK. British Poultry Science, 51(4): 488-499 although it does occur in other poultry such as pheasants,Butler, D.A. and Davis, C. 2010. Effects of plastic bits on the condition and behaviour of captive-reared pheasants. Veterinary. Record, 166: 398-401 turkeys,Sherwin, C.M., 2010. Turkeys: Behavior, Management and Well-Being. In “The Encyclopaedia of Animal Science”. Wilson G. Pond and Alan W. Bell (Eds). Marcel Dekker. pp. 847-849 ducks,Gustafson, L.A., Cheng, H.W., Garner, J.P., et al. 2007. Effects of bill-trimming Muscovy ducks on behavior, body weight gain, and bill morphopathology. Applied Animal Behaviour Science, 103: 59-74 broiler chickens and is sometimes seen in farmed ostriches.Reischl, E. and Sambraus, H.H. 2003. Feather-pecking of African ostriches in Israel. Tierarztliche Umschau, 58: 364-369 Feather pecking occurs when one bird repeatedly pecks at the feathers of another. The levels of severity may be recognized as mild and severe.McAdie, T.M. and Keeling, L.J. 2002. The social transmission of feather pecking in laying hens: effects of environment and age. Applied Animal Behaviour Science, 75: 147-159 Gentle feather pecking is considered to be a normal investigatory behaviour where the feathers of the recipient are hardly disturbed and therefore does not represent a problem. In severe feather pecking, however, the feathers of the recipient are grasped, pulled at and sometimes removed. This is painful for the receiving birdGentle, M.J. and Hunter, L.N. 1991. Physiological and behavioural responses associated with feather removal in Gallus gallus var domesticus. Research in Veterinary Science, 50: 95-101 and can lead to trauma of the skin or bleeding, which in turn can lead to cannibalism and death.
Feather pecking is one of the major problems facing the egg industry in non-cage systems and is set to become an even greater issue with the EU legislation (Council Directive 1999/74/EC) ban on the keeping of laying hens in barren battery cages which came into force in 2012, and the prospect of a ban on beak-trimming (see below). Reducing feather pecking without resorting to beak-trimming is an important goal for the poultry industry.
Motivational basis Feather pecking is considered to be re-directed behaviour, developing either from ground peckingBlokhuis, H.J., 1986. Feather-pecking in poultry: its relation with ground-pecking. Applied Animal Behaviour Science, 16: 63–67 or pecking during dustbathing,Vestergaard, K.S., Lisborg, L., 1993. A model of feather pecking development which relates to dustbathing in the fowl. Behaviour, 126: 291–308 although the former hypothesis is now the more favoured.Rodenburg, B.T., Komen, H., Ellen, E.D., Uitdehaag, K.A. and van Arendonk, J.A., 2008. Selection method and early-life history affect behavioural development, feather pecking and cannibalism in laying hens: A review. Applied Animal Behaviour Science 110: 217–228Dixon, L.M., 2008. Feather pecking behaviour and associated welfare issues in laying hens. Avian Biology Research, 1: 73-87Dixon, L.M., Duncan, I.J.H. and Mason, G.J., 2010. The effects of four types of enrichment on feather-pecking behaviour in laying hens housed in barren environments. Animal Welfare, 19: 429-435 Captive birds are very often kept in barren environments with limited foraging opportunities and in addition, are usually fed a nutrient-dense diet which can be eaten in a few minutes rather than the hours it would require to acquire during normal foraging. In combination, these cause the birds' foraging activity to be re-directed to the feathers of their conspecifics.
Feather pecking is not aggression. During aggressive encounters, hens peck exclusively at the top of the head or the comb, whereas during feather pecking, the areas of the body that are usually targeted are the base of the tail over the uropygial or preen gland, the back, the tail feathers and the wing feathers. Although feather pecking activity may be related to dominance relationships or the pecking order, formation of the dominance hierarchy is not involved in the causation of feather pecking. Feather pecking is also distinct from another psychopathological behaviour called feather-plucking or feather-picking. In feather-plucking, birds, often housed in isolation, remove feathers from their own body; in feather pecking, however, birds peck at each other's feathers.
Sometimes, feathers that are removed are then eaten, in which case the behaviour is termed "feather eating". Whilst there may be a positive association between feather pecking and eating, at least in the individual bird,McKeegan D.E.F and Savory, C.J. 1999. Feather eating in layer pullets and its possible role in the aetiology of feather pecking damage, Applied Animal Behaviour Science 65: 73–85McKeegan, D.E.F. and Savory, C.J., 2001. Feather eating in individually caged hens which differ in their propensity to feather peck. Applied Animal Behaviour Science, 73: 131-140 this is likely due to an overall higher pecking motivation.de Haas, E.N., Nielsen, B.L., Buitenhuis, A.J. and Rodenburg, T.B., 2010. Selection on feather pecking affects response to novelty and foraging behaviour in laying hens. Applied Animal Behaviour Science, 124: 90-96 Eating feathers increases gut transitHarlander-Matauschek, A., Piepho, H.P. and Bessei, W., 2006. The effect of feather eating on feed passage in laying hens. Poultry Science, 85: 21-25 indicating that feather pecking and feather eating have a different motivational basis.
Development
Early experience can influence severe feather pecking in later life.Drake, K.A., Donnelly, C.A. and Stamp Dawkins, M., 2010. Influence of rearing and lay risk factors on propensity for feather damage in laying hens. British Poultry Science, 51: 725—733 Commercial egg-laying hens have often already begun feather pecking when they are transferred to the egg laying farm from the rearing farm at approximately 16–20 weeks of age, and plumage quality can then rapidly deteriorate until peak lay at approximately 25 weeks of age. Severe feather pecking can either begin or persist beyond this age although it rarely begins after 40 weeks of age.Bright, 2010. Plumage damage in commercial layers. Veterinary Record,164: 334-335
Although there are links between gentle feather pecking and severe feather pecking, it is still not clear whether the gentle form leads to the severe form.
Some areas of the body are targeted for feather pecking and there is a pattern in the development of which areas are pecked. The rump area over the uropygial gland and the tail are often the first body regions to show signs of plumage damage due to feather pecking, followed by the neck, wings and back,Bilcik, B. and Keeling, L.J., 1999. Changes in feather condition in relation to feather pecking and aggressive behaviour in laying hens. British Poultry Science 40: 444-451 although in the ostrich which has a similar pattern of feather pecking development, the uropygial gland is absent.
Prevalence
Although feather pecking occurs in all commercial housing systems used for egg laying hens, it is often more prevalent or severe in loose flock systemsKeeling, L.J., 1995. Feather pecking and cannibalism in layers. Poultry International, 46: 50 because it is less easy to control and can spread more rapidly. Prevalence figures range between 57 and 86% of free-range flocksLambton, S.L., Knowles, T.G., Yorke, C. and Nicol, C.J., 2010. The risk factors affecting the development of gentle and severe feather pecking in loose housed laying hens. Applied Animal Behaviour Science 123: 32–42Green, L.E., Lewis, K., Kimpton, A. and Nicol, C.J., 2000. Cross-sectional study of the prevalence of feather pecking in laying hens in alternative systems and its association with management and disease. Veterinary Record, 147: 233-238Bestman, M.W.P. and Wagenaar, J.P. 2003. Farm level factors associated with feather pecking in organic laying hens. Livestock Production Science, 80: 133–140 and 99% of hens within a flock can be affected. The UK national flock of egg laying hens is currently (2011) approximately 33 million birds of which approximately 10 million are free-range. This indicates that 5.5 million free-range hens/year are likely to be affected by feather pecking. It has been estimated that 4% of hens on free-range farms die because of feather pecking, representing 220,000 deaths each year in the UK alone due to this behavioural problem. EU legislation (Council Directive 1999/74/EC) will ban battery or conventional cages in 2012 meaning that many producers will change to using free-range systems, possibly exacerbating this welfare problem until effective methods of its control are learned - see Defra's "A Guide To The Practical Management of Feather Pecking & Cannibalism in Free Range Laying Hens" A Guide To The Practical Management of Feather Pecking & Cannibalism in Free Range Laying Hens, DEFRA, 2005, retrieved: December 2012
Risk factors
Feather pecking is a multifactorial problem and a large number of risk factors have been identified for commercial flocks.Potzsch, C.J., Lewis, K., Nicol, C.J. and Green, L.E. 2001. A cross-sectional study of the prevalence of vent pecking in laying hens in alternative systems and its associations with feather pecking, management and disease. Applied Animal Behaviour Science, 74: 259–272Drake, K.A., Donnelly, C.A and Stamp Dawkins, M. 2010. Influence of rearing and lay risk factors on propensity for feather damage in laying hens. British Poultry Science, 51: 725-733
Factors likely to reduce feather pecking are:
Diet Minimal number of diet changes Ad libitum feeding Mashed feed rather than pelleted Diet balanced for protein and methionine Dietary tryptophan
Genetics White breeds such as the Amberlink compared to pigmented breeds Less flighty breeds
Housing and husbandry Dark brooders Purchasing the hens at an earlier age and allowing them on the range earlier Delaying the onset of lay Maintaining a uniform flock (purchase single flocks and do not mix) Pan feeders rather than chain feeders Nipple drinkers rather than bell drinkers Good litter quality Good air quality (low levels of ammonia and carbon dioxide) Decreased light intensity Decreased noise levels House temperature above 20 °C (68 °F) Multiple persons inspecting the hens Minimal light changes for inspection Avoiding using lights in nest boxes
Hen behaviour Increased use of the range (e.g. smaller flocks, increasing shelter, cockerels) Reduced fearfulness
Health Good health, especially avoiding egg peritonitis and infectious bronchitis
Methods of control
Beak-trimming