Affiliation: | 1.Department of Anthropology/Sociobiology, University of Göttingen, Göttingen, Germany ;2.Institute of Behavioural Physiology, Research Institute for Farm Animal Biology (FBN), Dummerstorf, Germany ;3.Animal Husbandry, Behaviour and Welfare Unit, Department of Animal Breeding and Genetics, University of Giessen, Giessen, Germany ; |