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Feather pecking is a behavioural problem 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: 223–231〕〔Sherwin, 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〕 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. Two levels of severity are recognised, gentle 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 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 bird〔Gentle, 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)〔http://www.eurlex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:1999:203:0053:0057:EN:PDF〕 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 pecking〔Blokhuis, 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: 217–228〕〔Dixon, L.M., 2008. Feather pecking behaviour and associated welfare issues in laying hens. Avian Biology Research, 1: 73-87〕〔Dixon, 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: 73–85〕〔McKeegan, 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 transit〔Harlander-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. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Feather pecking」の詳細全文を読む スポンサード リンク
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