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Effects of age, sex and social isolation on contrafreeloading in red junglefowl (Gallus gallus) and White Leghorn fowl
Linköping University, Department of Physics, Chemistry and Biology, Zoology . Linköping University, The Institute of Technology.
Linköping University, Department of Physics, Chemistry and Biology, Zoology . Linköping University, The Institute of Technology.
2008 (English)In: Applied Animal Behaviour Science, ISSN 0168-1591, E-ISSN 1872-9045, Vol. 114, no 3-4, 419-428 p.Article in journal (Refereed) Published
Abstract [en]

Contrafreeloading (CFL), i.e. choosing to work to obtain food over free food, has been studied in many different species. White Leghorn laying hens selected for high production have a lower extent of CFL compared to their wild ancestor, red junglefowl. We studied the effects of age, sex and social isolation. on the extent of CFL in red junglefowl and White Leghorn layers.

For 48 h, 30 birds of each breed were allowed a choice, between freely available food and food mixed with wood shavings. Both females and males were tested individually as young birds (8-10 weeks old) and when they were sexually mature (27-29 weeks old). To test the possible effects of social isolation, the same birds were also tested in pairs at 30 weeks of age.

Junglefowl showed a higher extent of CFL at the younger age compared to Leghorns (33.7% vs. 22.7%: P = 0.05) and both breeds showed higher extent of CFL at a young age than when sexually mature (P < 0.001). There were no significant differences between the two breeds when they were sexually mature and tested individually but, when tested in pairs, junglefowl showed higher extent of CFL than Leghorns (31.7% vs. 17.0%; P < 0.001). There were no differences in the extent of CFL between the sexes in either breed.

The results indicate that age and social isolation influence the extent of CFL in fowl. Furthermore, the results support earlier findings that the extent of CFL is lower in Leghorns than junglefowl, indicating a possible side-effect of selection for increased production.

Place, publisher, year, edition, pages
2008. Vol. 114, no 3-4, 419-428 p.
Keyword [en]
Domestication, Contrafreeloading, Junglefowl, White Leghorn, Age, Social isolation
National Category
Natural Sciences
URN: urn:nbn:se:liu:diva-16127DOI: 10.1016/j.applanim.2008.03.002OAI: diva2:133209
Available from: 2009-01-08 Created: 2009-01-07 Last updated: 2011-01-11Bibliographically approved
In thesis
1. Domestication effects on foraging behaviour: consequences for adaptability in chickens
Open this publication in new window or tab >>Domestication effects on foraging behaviour: consequences for adaptability in chickens
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The main aim of this thesis was to study domestication effects on foraging behaviour in chickens and to investigate whether and how domestication and selection for high production have influenced adaptability in chickens. Two domestic strains of chickens (egg layers and meat type chickens) and their wild ancestor, the red jungle fowl (RJF) were compared in different test situations with respect to foraging behaviour and adaptability. The domestic strains showed a modified foraging strategy, where they were less inclined to explore and feed from a hidden food source, i.e. they showed less contrafreeloading (CFL, the behaviour of working for food even though identical food can be easily obtained) than RJF. The difference in CFL between RJF and the layers were not altered by food deprivation, which suggests that the lower CFL in the layers represents a genetically based difference in feeding strategy. In addition, CFL decreased with age in RJF and layers and social isolation decreased CFL in RJF. Furthermore, when foraging, RJF acquired information about the quality of different food sources, which was utilised after a change in environmental conditions. Contrary to this, layers gained less information during foraging and showed an impaired spatial learning ability compared to RJF, and in this respect, layers showed a lower degree of adaptability. Chronic stress impaired the learning capacity of both breeds but RJF seemed to be overall faster to learn to locate food in a spatial learning task. Furthermore, stressed RJF started to eat faster in the spatial learning test than non-stressed RJF, and contrary to this, stressed layers showed a more passive response by prolonging the time to start feeding compared to non-stressed layers. This indicates a more active response to stress in RJF than in layers. Similarly, when RJF and layers were exposed to food deprivation, RJF showed an active response by increasing their time spent on foraging behaviour. The general results in this thesis most likely reflect different adaptive strategies, where RJF appear to be better adapted to a stochastic environment, and the domestic strains to grow and produce egg in a more predictable environment. The findings are in accordance with the resource allocation theory, which suggests that animals selected for high production are expected to reallocate a high proportion of resources into production traits and hence fewer resources might be left to other biological processes, e.g. exploratory behaviour. Selection for high production seems to influence the ability of chickens to cope with a changing environment, which may have implications for the welfare of chickens in a production environment.

Place, publisher, year, edition, pages
Institutionen för fysik, kemi och biologi, 2008. 37 p.
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1164
Etologi, chicken, domestication effects, behaviour, red jungle fowl (RJF), contrafreeloading (CFL), egg production
National Category
urn:nbn:se:liu:diva-11237 (URN)978-91-7393-969-0 (ISBN)
Public defence
2008-03-28, Planck, Fysikhuset, Campus Valla, Linköpings universitet, Linköping, 10:15 (English)
Available from: 2008-03-11 Created: 2008-03-11 Last updated: 2010-01-13Bibliographically approved

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