Dominic Wright1, Rie Henriksen2, Martin Johnsson3. 1. AVIAN Behavioural Genomics and Physiology group, IFM Biology, Linköping University, Linköping, 58183, Sweden. Electronic address: dominic.wright@liu.se. 2. AVIAN Behavioural Genomics and Physiology group, IFM Biology, Linköping University, Linköping, 58183, Sweden. 3. The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Edinburgh, EH25 9RG, UK; Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden.