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Genetic and physiological factors influencing feather pecking in chickens

Published online by Cambridge University Press:  17 December 2010

M. WYSOCKI ,
W. BESSEI ,
J.B. KJAER  and
J. BENNEWITZ
M. WYSOCKI*
Affiliation:
Institute of Animal Husbandry and Animal Breeding, University of Hohenheim, 70599 Stuttgart, Germany
W. BESSEI
Affiliation:
Institute of Animal Husbandry and Animal Breeding, University of Hohenheim, 70599 Stuttgart, Germany
J.B. KJAER
Affiliation:
Friedrich-Loeffler-Institute, Federal Research Centre for Animal Health, Institute of Animal Welfare and Animal Husbandry, 29223 Celle, Germany
J. BENNEWITZ
Affiliation:
Institute of Animal Husbandry and Animal Breeding, University of Hohenheim, 70599 Stuttgart, Germany
*
Corresponding author: [email protected]
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Abstract

Feather pecking is a major welfare problem in egg production. It may be caused by endogenous (genetic and physiological) and environmental (feeding, density and housing conditions) factors. Despite the number and variety of experiments performed over past years, it is still not possible to define a genetic background for this trait. A possible reason is the complex nature of feather pecking, but also the lack of a homogenous approach in the studies conducted. The present paper summarizes recent findings regarding genetic and physiological components of feather pecking. Furthermore, it emphasizes the need for complex study combining a selection experiment together with the power of molecular biology and bioinformatics.

Keywords

feather peckinggeneticsphysiologybehaviourchicken
Type
Review Article
Information
World's Poultry Science Journal , Volume 66 , Issue 4 , December 2010 , pp. 659 - 672
Copyright
Copyright © World's Poultry Science Association 2010

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References

ALBENTOSA, M.J., KJAER, J.B. and NICOL, C.J. (2003) Strain and age differences in behaviour, fear response and pecking tendency in laying hens. British Poultry Science 44: 333-344.Google Scholar
ALLEN, J. and PERRY, G.C. (1975) Feather pecking and cannibalism in a caged layer flock. British Poultry Science 57: 441-451.Google Scholar
BAUM, S. (1992) Zur Genese der Verhaltensstoerung Federpicken. KTBL-Schrift 351: 60-68.Google Scholar
BELL, D.D., ADAMS, C.J. and GVARYAHU, G. (1998) Environment enrichment devices for caged laying hens. Journal of Applied Poultry 7: 19-26.Google Scholar
BEN-SHAHAR, Y., ROBICHON, A., SOKOLOWSKI, M.B. and ROBINSON, G.E. (2002) Influence of gene action across different time scales on behaviour. Science 296: 741-744.CrossRefGoogle Scholar
BEN-SHAHAR, Y. (2005) The foraging gene, behavioural plasticity, and honeybee division of labor. Journal of Comparative Physiology 191: 987-994.Google Scholar
BESSEI, W. (1980) Untersuchungen über Furcht und Scheu bei Hennen. Hohenheimer Arbeiten 108: 9-12.Google Scholar
BESSEI, W. (1983) Zum Problems der Federpickens und Kannibalismus. Deutsche Gefluegelwirtschefat und Schweinproduktion 24: 656-665.Google Scholar
BESSEI, W. (1984) Untersuchungen zur Heritabilität des Federpickverhaltens bei Junghennen. I. Mitteilung Archiv für Geflügelkunde 48(6): 224-231.Google Scholar
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.Google Scholar
BILCIK, B. and KEELING, L.J. (2000) Relationship between feather pecking and ground pecking in laying hens and the effect of group size. Applied Animal Behaviour Science 68: 55-66.Google Scholar
BLOKHUIS, H.J. and ARKES, J.G. (1984) Some observations on the development of feather-pecking in poultry. Applied Animal Behaviour Science 12: 145–157.Google Scholar
BLOKHUIS, H.J. (1986) Feather-pecking in poultry: Its relation with ground-pecking. Applied Animal Behaviour Science 16: 63-67.Google Scholar
BLOKHUIS, H.J., VAN DER HAAR, J.W. and KOOLE, P.G. (1987) Effects of beak trimming and floor type on feed consumption and body weight of pullets during rearing. Poultry Science 66(4): 623-625.CrossRefGoogle ScholarPubMed
BLOKHUIS, H.J. and BEUTLER, A. (1992) Feather pecking damage and tonic immobility response in two lines of White Leghorn hens. Journal of Animal Science 70(Suppl. 1): 170.Google Scholar
BLOKHUIS, H.J. and VAN DER HAAR, J.W. (1992) Effects of pecking incentives during rearing on feather pecking of laying hens. British Poultry Science 33(1): 17-24Google Scholar
BLOKHUIS, H.J. and WIEPKEMA, P.R. (1998) Studies of feather pecking in poultry. Veterinary Quarterly 20: 6-9.CrossRefGoogle ScholarPubMed
BOLHUIS, J.E., ELLEN, E.D., VAN REENEN, C.G., DE GROOT, J., NAPEL, J.T., KOOPMANSCHAP, R.E., DE VRIES REILINGH, G., UITDEHAAG, K.A., KEMP, B. and RODENBURG, T.B. (2009) Effects of genetic group selection against mortality on behaviour and peripheral serotonin in domestic laying hens with trimmed and intact beaks. Physiology & Behavior 97(3-4): 470-475.Google Scholar
BRIGHT, A. (2007) Plumage colour and feather pecking in laying hens, a chicken perspective? British Poultry Science 48(3): 253-63.CrossRefGoogle Scholar
BUITENHUIS, A.J., RODENBURG, T.B., VAN HIERDEN, Y.M., SIWEK, M., CORNELISSEN, S.J.B., NIEUWLAND, M.G.B., CROOIJMANS, R.P.M.A., GROENEN, M.A.M., KOENE, P. and KORTE, S.M. (2003a) Mapping quantitative trait loci affecting feather pecking behaviour and stress response in laying hens. Poultry Science 82: 1215-1222.CrossRefGoogle ScholarPubMed
BUITENHUIS, A.J., RODENBURG, T.B., SIWEK, M., CORNELISSEN, S.J.B., NIEUWLAND, M.G.B., CROOIJMANS, R.P.M.A., GROENEN, M.A.M., KOENE, P., BOVENHUIS, H. and VAN DER POEL, J.J. (2003b) Identification of Quantitative Trait Loci for Receiving Pecks in Young and Adult Laying Hens. Poultry Science 82: 1661-1667.Google Scholar
BUITENHUIS, A.J., RODENBURG, T.B., SIWEK, M., CORNELISSEN, S.J.B., NIEUWLAND, M.G.B., CROOIJMANS, R.P.M.A., GROENEN, M.A.M., KOENE, P., BOVENHUIS, H. and VAN DER POEL, J.J. (2004) Identification of QTLs Involved in Open-Field Behaviour in Young and Adult Laying Hens. Behavior Genetics 34: 325-333.CrossRefGoogle Scholar
BUITENHUIS A.J., , RODENBURG, T.B., SIWEK, M., CORNELISSEN, S.J.B., NIEUWLAND, M.G.B., CROOIJMANS, R.P.M.A., GROENEN, M.A.M., KOENE, P., BOVENHUIS, H. and VAN DER POEL, J.J. (2005) Quantitative trait loci for behavioural traits in chickens. Livestock Production Science 93: 95–103.Google Scholar
BUITENHUIS, A.J. and KJAER, J.B. (2008) Long term selection for reduced or increased pecking behaviour in laying hens. World's Poultry Science Journal 64: 16-20.Google Scholar
CHENG, H.W., DILLWORTH, G., SINGLETON, P., CHEN, Y. and MUIR, W.M. (2001) Effects of Group Selection for Productivity and Longevity on Blood Concentrations of Serotonin, Catecholamines, and Corticosterone of Laying Hens. Poultry Science 80: 1278–1285.CrossRefGoogle ScholarPubMed
CRAIG, J.V. and MUIR, W.M. (1989) Fearful and associated responses of caged White Leghorns hens: genetic parameter estimates. Poultry Science 68: 1040-1046.Google Scholar
CRAIG, J.V. and MUIR, W.M. (1993) Selection for reduction of beak-inflicted injuries among caged hens. Poultry Science 72: 411–420.CrossRefGoogle Scholar
CUTHERTSON, G.J. (1978) An ethological investigation of feather pecking. Ph.D. Thesis, University of Edinburgh.Google Scholar
DAVARSI, A. and SOLLER, M. (1995) Advanced intercross lines, an experimental population for fine genetic mapping. Genetics 141: 1199–1207.Google Scholar
DE BELLE, J.S., HILLIKER, A.J. and SOKOLOWSKI, M.B. (1989) Genetic localization of foraging (for): A major gene for larval behaviour in Drosophila melanogaster. Genetics 123: 157-163.Google Scholar
DENNIS, R.L., CHEN, Z.Q. and CHENG, H.W. (2008) Serotonergic mediation of aggression in high and low aggressive chicken strains. Poultry Science 87(4): 612-20.CrossRefGoogle ScholarPubMed
FIDLER, A.E., VAN OERS, K., DRENT, P.J., KUHN, S., MUELLER, J.C. and KEMPENAERS, B. (2007) DRD4 gene polymorphisms are associated with personality variation in a passerine bird. Proceedings: Biological Sciences 274: 1685–91.Google Scholar
FLINT, J. (2003) Analysis of Quantitative Trait Loci That Influence Animal Behavior. Journal of Neurobiology 53: 46-77.Google Scholar
FLISIKOWSKI, K., SCHWARZENBACHER, H., WYSOCKI, M., WEIGEND, S., PREISINGER, R., KJAER, J.B. and FRIES, R. (2009) Variation in neighbouring genes of the dopaminergic and serotonergic systems affects feather pecking behaviour of laying hens. Animal Genetics 40(2): 192-199.CrossRefGoogle ScholarPubMed
GALEF, B.G. (1988) Imitation in animals: history, definition, and interpretation of data from the psychological laboratory, in: ZENTALL, T.R. & GALEF, B.G. (Eds) Social Learning: Psychological and Biological Perspectives, pp. 3-28.Google Scholar
GVARYAHU, G., ARARAT, E., ASAF, E., LEV, M., WELLER, J.I., ROBINZON, B. and SNAPIR, N. (1994) An enrichment object that reduces aggressiveness and mortality in caged laying hens. Physiology and Behaviour 55: 313-316.Google Scholar
HÄUSLER, K. (2008) Untersuchungen zur Motivation zum Federfressen bei Legehennen. Ph. D. Thesis, Institut of Farm Animal Ethology and Poultry Production, University of Hohenheim.Google Scholar
HOCKING, P.M., CHANNING, C.E., ROBERTSON, G.W., EDMOND, A. and JONES, R.B. (2004) Between breed genetic variation for welfare-related behavioural traits in domestic fowl. Applied Animal Behaviour Science 89: 85-105.Google Scholar
HUBER-EICHER, B. and WECHSLER, B. (1997) Feather pecking in domestic chicks: its relation to dustbathing and foraging. Animal Behavior 54: 757-768.CrossRefGoogle ScholarPubMed
HUBER-EICHER, B. and WECHSLER, B. (1998) The effect of quality and availability of foraging materials on feather pecking in laying hen chicks. Animal Behavior 55: 861-873.Google Scholar
HUGHES, B.O. and DUNCAN, I.J. (1972) The influence of strain and environmental factors upon feather pecking and cannibalism in fowls. British Poultry Science 13: 525-547.CrossRefGoogle ScholarPubMed
HUGHES, B.O. (1973) The effect of implanted gonadal hormones on feather pecking and cannibalism in pullets. British Poultry Science 14(4): 341-348.Google Scholar
HUGHES, B.O. (1982) Feather pecking and cannibalism in domestic fowls. Disturbed Behaviour in Farm Animals. Hohenheimer Arbeiten 121: 138-14Google Scholar
HURNIK, J.F., WEBSTER, A.B. and SIEGEL, P.B. (1995) Dictionary of Farm Animal Behaviour, second edition. Iowa State University Press.Google Scholar
JANSEN, R.C. and NAP, J.P. (2001) Genetical genomics: the added value from seggregation. Trends in Genetics 17: 388-391.Google Scholar
JENSEN, P., KEELING, L., SCHÜTZ, K., ANDERSSON, L., KERJE, S., CARLBORG, , Ö., and JACOBSON, L. (2003) Feather pecking in poultry – phenotypic correlations and QTL-analysis in F2-intercross between red jungle fowl and white leghorn layers. Proceedings of the 37th ISAE International Congress In Ferrante V (Ed) Fondazione Iniziative Zooprofilattiche e Zootecniche, Brescia, Abano Terme Italy, June 24-28, pp. 68-69.Google Scholar
JENSEN, P., KEELING, L., SCHÜTZ, K., ANDERSSON, L., MORMEDE, P., BRÄNDSTRÖM, H., FORKMAN, B., KERJE, S., FREDRIKSSON, R., OHLSSON, C., LARSSON, S., MALLMIN, H. and KINDMARK, A. (2005) Feather pecking in chickens is genetically related to behavioural and developmental traits. Physiology & Behavior 86:52-60.Google Scholar
JIMÉNEZ-MARÍN, A., COLLADO-ROMERO, M., RAMIREZ-BOO, M., ARCE, C. and GARRIDO, J.J. (2009) Biological pathway analysis by ArrayUnlock and Ingenuity Pathway Analysis. BMC Proceedings 16:3 Suppl 4:S6.Google Scholar
JOHNSEN, P.F., VESTERGAARD, K.S. and NORGAARD-NIELSEN, G. (1998) Influence of early rearing conditions on the development of feather pecking and cannibalism in domestic fowl. Applied Animal Behaviour Science 60: 25-41.Google Scholar
KEELING, L.J. (1994) Feather pecking—who in the group does it, how often and under what circumstances? Proceedings of the 9th European Poultry Conference, Glasgow.Google Scholar
KEELING, L.J. (1995) Feather pecking and cannibalism in layers. Poultry International 6: 46-50.Google Scholar
KEELING, L., ANDERSSON, L., SCHUTZ, K.E., KERJE, S., FREDRIKSSON, R., CARLBORG, O., CORNWALLIS, C.K., PIZZARI, T. and JENSEN, P. (2004) Chicken genomics: feather-pecking and victim pigmentation. Nature 431: 645-646.Google Scholar
KERJE, S., SHARMA, P., GUNNARSSON, U., KIM, H., BAGCHI, S., FREDRIKSSON, R., SCHÜTZ, K., JENSEN, P., VON HEIJNE, G., OKIMOTO, R. and ANDERSSON, L. (2004) The Dominant white, Dun and Smoky colour variants in chicken are associated with insertion/deletion polymorphisms in the PMEL17 gene. Genetics 168(3): 1507-18.Google Scholar
KJAER, J.B. and SØRENSEN, P. (1997) Feather pecking behaviour in White Leghorns, a genetic study. British Poultry Science 38: 333-341.Google Scholar
KJAER, J.B. and VESTERGAARD, K.S. (1999) Development of feather pecking in relation to light intensity. Applied Animal Behaviour Science 62: 243-254.Google Scholar
KJAER, J.B. (2000) Diurnal rhythm of feather pecking behaviour and condition of integument in four strains of loose housed laying hens. Applied Animal Behaviour Science 65: 331-347.Google Scholar
KJAER, J.B., SØRENSEN, P. and SU, G. (2001) Divergent selection on feather pecking behaviour in laying hens (Gallus gallus domesticus). Applied Animal Behaviour Science 71: 229-239.CrossRefGoogle ScholarPubMed
KJAER, J.B., HJARVARD, B.M., JENSEN, K.H., HANSEN-MÜLLER, J. and NAESBYE LARSEN, O. (2004) Effects of haloperidol, a dopamine D2 antagonist, on feather pecking behaviour in laying hens. Applied Animal Behaviour Science 86: 77-91.Google Scholar
KJAER, J.B. (2009) Feather Pecking in Domestic Fowl is Genetically Related to Locomotor Activity Levels: Implications for a Hyperactivity Disorder Model of Feather Pecking. Behavior Genetics 39: 564–570.Google Scholar
KLEIN, T., ZELTNER, E. and HUBER-EICHER, B. (2000) Are genetic differences in foraging behaviour of laying hen chicks paralleled by hybrid-specific differences in feather pecking? Applied Animal Behaviour Science 70: 143-155.Google Scholar
KORTE, S.M., BEUVING, G., RUESINK, W. and BLOKHUIS, H.J. (1997) Plasma catecholamine and corticosterone levels during manual restraint in chicks from a high and low feather pecking line of laying hens. Physiology & Behavior 62: 437-441.CrossRefGoogle ScholarPubMed
KORTE, S.M. (2001) Corticosteroids in relation to fear, anxiety and psychopathology. Neuroscience & Biobehavioral Reviews 25: 117-142.Google Scholar
LABOURIAU, R., KJAER, J.B., ABREU, G.C.G., HEDEGAARD, J. and BUITENHUIS, A.J. (2009) Analysis of severe feather pecking behaviour in a high feather pecking selection line. Poultry Science 88: 2052-2062.Google Scholar
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.Google Scholar
MCKEEGAN, D.E. 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.Google Scholar
MEUWISSEN, T.H., KARLSEN, A., LIEN, S., OLSAKER, I. and GODDARD, M.E. (2002) Fine mapping of a quantitative trait locus for twinning rate using combined linkage and linkage disequilibrium mapping. Genetics 161(1): 373379.Google Scholar
NÄTT, D., KERJE, S., ANDERSSON, L. and JENSEN, P. (2007) Plumage colour and feather pecking-behavioural differences associated with PMEL17 genotypes in chicken (Gallus gallus). Behaviour Genetics 37(2): 399-407.Google Scholar
NEWBERRY, R.C., KEELING, L.J., ESTEVEZ, E. and BILCIK, B. (2007) Behaviour when young as a predictor of severe feather pecking in adult laying hens: The redirected foraging hypothesis revisited. Applied Animal Behaviour Science 107: 262-274.CrossRefGoogle Scholar
NICOL, C.J. (1995) The social transmission of information and behaviour. Applied Animal Behaviour Science 44: 79-98.Google Scholar
OETTEL, R. (1873) Der Hühner oder Geflügelhof. Bernhard Friedrich Boigt, Weimar.Google Scholar
QUART, M.D. and ADAMS, A.W. (1982) Effects of cage design and bird density on layers. 1. Productivity, feathering and nervousness. Poultry Science 61: 1606-1613.Google Scholar
RIEDSTRA, B. and GROOTHUIS, T. (2002) Early feather pecking as a form of social exploration: the effect of group stability on feather pecking and tonic immobility in domestic chicks. Applied Animal Behaviour Science 77: 127-138.Google Scholar
RODENBURG, T.B., ZIMMERMAN, P.H. and KOENE, P. (2002) Reaction to frustration in high and low feather pecking laying hens. Behavioural Processes 59:121-129.Google Scholar
RODENBURG, T.B., BUITENHUIS, A.J., ASK, B., UITDEHAAG, K.A., KOENE, P., VAN DER POEL, J.J. and BOVENHUIS, H. (2003) Heritability of feather pecking and open-field response of laying hens at two different ages. Poultry Science 82: 861-867.CrossRefGoogle ScholarPubMed
RODENBURG, T.B., KOENE, P. and SPRUIJT, B.M. (2004a) Reaction to frustration in high and low feather pecking lines of laying hens from commercial or semi-natural rearing conditions. Behavioural Processes 65: 179-188.Google Scholar
RODENBURG, T.B., BUITENHUIS, A.J., ASK, B., UITDEHAAG, K.A., KOENE, P., VAN DER POEL, J.J., VAN ARENDONK, J.A. and BOVENHUIS, H. (2004b) Genetic and phenotypic correlations between feather pecking and open-field response in laying hens at two different ages. Behaviour Genetics 34(4): 407-15.Google Scholar
RODENBURG, T.B., VAN HIERDEN, Y.M., BUITENHUIS, A.J, RIEDSTRA, B., KOENE, P., KORTE, S.M., VAN DER POEL, J.J., GROOTHUIS, T.G.G. and BLOKHUIS, H.J. (2004c) Feather pecking in laying hens: new insights and directions for research? Applied Animal Behaviour Science 86: 291-298.Google Scholar
RUDKIN, C. (1996) Pecking enrichment for intensively housed chickens. Advances in Animal Behaviour and Welfare in Australasia and Africa. Proceedings of the 1st Regional Meeting of the International Society of Applied Ethology, Christchurch, New Zealand, pp. 12.Google Scholar
SAVORY, C.J. (1995) Feather pecking and cannibalism. World's Poultry Science Journal 51: 215-219.Google Scholar
SAVORY, C.J. and MANN, J.S. (1997) Behavioural development in groups of pen-housed in relation to genetic strain, age and food form. British Poultry Science 38: 38-47.Google Scholar
SCHADT, E.E., MONKS, S.A., DRAKE, T.A., LUSIS, A.J., CHE, N., COLINAYO, V., RUFF, T.G., MILLIGAN, S.B., LAMB, J.R., CAVET, G., LINSLEY, P.S., MAO, M., STOUGHTON, R.B. and FRIEND, S.H. (2003) Genetics of gene expression surveyed in maize, mouse and man. Nature 422(6929): 297-302.Google Scholar
SCHÜTZ, K.E., KERJE, S., CARLBORG, O., JACOBSSON, L., ANDERSSON, L. and JENSEN, P. (2002) QTL analysis of a red junglefowl x White Leghorn intercross reveals trade-off in resource allocation between behaviour and production traits. Behavior Genetics 32(6): 423-33.CrossRefGoogle ScholarPubMed
SCHÜTZ, K.E., KERJE, S., JACOBSSON, L., FORKMAN, B., CARLBORG, O., ANDERSSON, L. and JENSEN, P. (2004) Major growth QTLs in fowl are related to fearful behaviour: possible genetic links between fear responses and production traits in a red junglefowl x white leghorn intercross. Behavior Genetics 34(1): 121-30.Google Scholar
SOKOLOWSKI, M.B. (1980) Foraging strategies of Drosophila melanogaster: A chromosomal analysis. Behavior Genetics 10:291-302.Google Scholar
SU, G., KJAER, J.B. and SØRENSEN, P. (2005) Variance components and selection response for feather-pecking behavior in laying hens. Poultry Science 84:14–21.Google Scholar
SU, G., KJAER, J.B. and SØRENSEN, P. (2006) Divergent selection on feather pecking behavior in laying hens has caused differences between lines in egg production, egg quality, and feed efficiency. Poultry Science 85:191197.Google Scholar
VAN HIERDEN, Y.M., KORTE, S.M., RUESINK, E.W., VAN REENEN, C.G., ENGEL, B., KORTE-BOUWS, G.A., KOOLHAAS, J.M. and BLOKHUIS, H.J. (2002a) Adrenocortical reactivity and central serotonin and dopamine turnover in young chicks from a high and low feather-pecking line of laying hens. Physiology & Behavior 75: 653-659.Google Scholar
VAN HIERDEN, Y.M., KORTE, S.M., RUESINK, E.W., VAN REENEN, C.G., ENGEL, B., KOOLHAAS, J.M. and BLOKHUIS, H.J. (2002b) The development of feather pecking behaviour and targeting of pecking in chicks from a high and low feather pecking line of laying hens. Applied Animal Behaviour Science 77: 183-196.Google Scholar
VAN HIERDEN, Y.M., DE BOER, S.F., KOOLHAAS, J.M. and KORTE, S.M. (2004) The control of feather pecking by serotonin. Behavioral Neuroscience 118: 575-583.Google Scholar
VAN HIERDEN, Y.M., KOOLHAAS, J.M., KOSTAL, L., VYBOH, P., SEDLACKOVA, M., RAJMAN, M., JURANI, M. and KORTE, S. (2005) Chicks from a high and low feather pecking line of laying hens differ in apomorphine sensitivity. Physiology & Behavior 84: 471-477.CrossRefGoogle ScholarPubMed
VESTERGAARD, K.S., KRUJITT, K.S. and HOGAN, J.A. (1993) Feather pecking and chronic fear in groups of red junglefowl: their relations to dustbathing, rearing environment and social status. Animal Behaviour 45: 18-23.Google Scholar
VESTERGAARD, K.S., SKADHAUGE, E. and LAWSON, L.G. (1997) The stress of not being able to perform dustbathing in laying hens. Physiology & Behavior 62: 413-419.Google Scholar
WANG, L., ERLANDSEN, H., HAAVIK, J., KNAPPSKOG, P.M. and STEVENS, R.C. (2002) Three-Dimensional Structure of Human Tryptophan Hydroxylase and Its Implications for the Biosynthesis of the Neurotransmitters Serotonin and Melatonin. Biochemistry 41: 12749-12754.Google Scholar
WECHSLER, B., HUBER-EICHER, B. and NASH, D.R. (1998) Feather pecking in growers: a study with individually marked birds. British Poultry Science 39(2): 178-85.Google Scholar
WYSOCKI, M., PREISINGER, R. and FRIES, R. (2006) Identification of candidate genes for feather pecking in chickens: evidence from behavioural and gene expression analyses. XII European Poultry Conference, Verona, Italy. World's Poultry Science Journal 62 (supplement): 206Google Scholar
WYSOCKI, M. (2007) Genetic dissection of the predisposition to feather pecking of laying hens: behavioural studies, identification of candidate genes and gene expression analyses. Ph.D. Thesis, Chair of Animal Breeding. Technical University of Munich.Google Scholar
ZELTNER, E., KLEIN, T. and HUBER-EICHER, B. (2000) Is there social transmission of feather pecking in groups of laying hen chicks? Animal Behaviour 60: 211-216.CrossRefGoogle ScholarPubMed