Feather pecking is a serious problem to the layer industry severely impairing animal welfare and causing economic losses. As a measure to control this unwanted behavior, beak trimming has been applied in the past, but is now banned in more and more countries including Germany. The propensity to perform feather pecking is a heritable trait. It can be reduced by means of breeding, but it is a hard-to-measure trait and to establish suitable selection schemes, knowledge of the genetic architecture of the trait is needed. Commercial flocks are of limited use for this research purpose for several reasons, but selection lines offer the possibility to realize advanced experimental designs. Here, a selective review on fundamental-type research is presented that has been conducted in the Hohenheim selection lines over the past years. Based thereon and the available literature, a mechanistic hypothesis about feather pecking is developed and it gives a perspective on implications for practical breeding.
