More eggs but less social and more fearful? Differences in behavioral traits in relation to the phylogenetic background and productivity level in laying hens

•Laying hens have undergone a strong selection pressure for egg productivity.•This has been proposed as a potential cause of side effects on behaviour.•We compared four purebred lines differing in egg yield and phylogenetic origin.•Egg productivity caused changes in sociality, while fear altered with phylogeny.•Allocation of resources were modified by recent intense selection for egg yield.