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A note on contrafreeloading in broilers compared to layer chicks
Linköping University, Department of Physics, Chemistry and Biology, Zoology . Linköping University, The Institute of Technology.
University of Bristol, Department of Farm Animal Science, United Kingdom.
Linköping University, Department of Physics, Chemistry and Biology, Zoology . Linköping University, The Institute of Technology.
2006 (English)In: Applied Animal Behaviour Science, ISSN 0168-1591, Vol. 101, no 1-2, 161-166 p.Article in journal (Refereed) Published
Abstract [en]

Contrafreeloading (CFL) is the behaviour where an animal chooses to work for food even when identical food can be obtained without any effort. Previous studies have suggested that the difference in CFL between White Leghorn layers and jungle fowl may be a side effect of selection for increased production traits in the Leghorn strain.

In this experiment we studied to what extent broilers chicks (Cobb/Ross), which are highly selected for fast growth, perform CFL and compared this with a layer strain (Calder Ranger), which grows considerably slower. We predicted that broilers should have a lower degree of CFL compared to the layer strain, as an energy-saving response to the demands of rapid growth.

During 48 h 10 pairs of each breed were given a choice between freely available food and food mixed with wood shavings. Behavioural observations were made twice each day. Broilers showed less CFL (p < 0.05), were more inactive (p < 0.001) and performed less active behaviours (p < 0.05) than layers.

Our results support previous findings that decreased CFL in domestic fowl may indicate adaptive reallocation of energy resources in response to selection for increased production traits.

Place, publisher, year, edition, pages
2006. Vol. 101, no 1-2, 161-166 p.
Keyword [en]
Contrafreeloading; Resource allocation; Broiler; Laying hen
National Category
Natural Sciences
URN: urn:nbn:se:liu:diva-13000DOI: 10.1016/j.applanim.2006.01.006OAI: diva2:17644
Available from: 2008-03-11 Created: 2008-03-11
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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