Quantitative trait loci for behavioural traits in chickens

The detection of quantitative trait loci (QTL) of behavioural traits has mainly been focussed on mouse and rat. With the rapid development of molecular genetics and the statistical tools, QTL mapping for behavioural traits in farm animals is developing. In chicken, a total of 30 QTL involved in pecking-related traits, open-field behaviour, tonic immobility, response to novel objects, and response to a restraint test were detected in different studies. In the search for a useful early predictor for feather pecking (FP) behaviour in adult laying hens, the following was found: FP in young animals is not a predictor for FP in adult animals, however, open-field behaviour in young animals is genetically correlated with FP in adult hens. Before the implementation of FP behaviour or open-field behaviour in breeding programmes, it is essential to know more about the correlation between these behavioural traits and also their relationship with production traits. Nevertheless, with the QTL for behavioural traits and the chicken genome sequence in progress, a better understanding of the underlying genetic mechanisms of behavioural traits will be feasible.