Rearing complexity affects fearfulness and use of vertical space in adult laying hens

M. Brandsaeter, J. Nordgreen, T.B. Rodenburg, F.M. Tahamtani, A. Popova, A.M. Janczak

Research output: Chapter in Book/Report/Conference proceedingAbstract


e complexity of the rearing environment is important for behavioral development in layinghens. is study aimed to test the hypothesis that laying hens reared in a complex aviarysystem would be less fearful and less sensitive to stress as adults than hens reared in barrencage environments. Laying hens (n=160) were reared in the same house, either kept insidethe aviary rows to imitate cages (n=80) or in the conventional aviary system (n=80). ebirds were then transported to the experimental facilities at 16 weeks of age and mix-housedin custom built pens. Two birds per treatment per pen where tested in human approach andnovel objct tests at 19 and 23 weeks of age. e results were analyzed by ANOVA on scores for afearfulness-related principal component, generated using principal component analysis. Flightresponses and the relationship between €ight response and fearfulness score were analyzed bylogistic regression. Use of vertical space was analyzed by Wilcoxon matched pairs signed ranktest. Aviary-reared (AV) birds had lower levels of fearfulness compared with cage-reared (C)birds both at 19 weeks (mean±std AV: 0.24±1.56; C: 0.74±1.72; F(1,19)=5.66; P=0.03) and at23 weeks (AV: -0.69±1.62; C: 0.19±2.11; F(1,19)=4.49; P=0.05) of age. At 19 weeks of age, moreaviary-reared birds tended to show a €ight response compared to cage-reared birds (OR=2.4;P=0.09) when initially exposed to a novel object. Rearing complexity did not a‚ect the €ightresponse at 23 weeks of age (OR=1.4; P=0.6). e odds ratio of showing a €ight response whenexposed to the novel object was not in€uenced by the principal component fearfulness score(OR=0.89; P=0.2). At 19 weeks of age, more aviary-reared birds spent time on the low perch(median, 25th-75th percentile AV: 20.8, 14.4-23.0; C: 12.5, 10.4-18.4; P=0.01), the elevatedplatform (AV: 19.2, 13.0-25; C: 12.1, 6.3-22.1; P=0.01) and upper perch (AV: 16.7, 10.4-23.0; C:5.2, 2.1-14.1; P<0.0001) compared to the cage-reared birds. However, at 23 weeks of age, thesedi‚erences were not detected (P>0.0001). Conclusively, increased environmental complexityduring rearing reduced fearfulness at 19 and 23 weeks of age and increased vertical space useat 19 weeks of age in laying hens.
Original languageEnglish
Title of host publicationProceedings of the 50th congress of the International Society for Applied Ethology
Subtitle of host publicationStanding on the shoulders of giants
EditorsCathy Dwyer, Marie Haskell, Victoria Sandilands
Place of PublicationWageningen, The Netherlands
PublisherWageningen Academic Publishers
Number of pages1
ISBN (Electronic)9789086868339
ISBN (Print)9789086862870
Publication statusPublished - 2016
Event50th Congress of the International Society for Applied Ethology - Edinburg, United Kingdom
Duration: 12 Jul 201615 Jul 2016


Conference50th Congress of the International Society for Applied Ethology
CountryUnited Kingdom

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