Defining normal: comparison of feed restriction and full feeding of female broiler breeders

Genetic selection for growth parameters in broiler stocks has created parent stocks that are unable to self-regulate feed intake to a level that permits reproductive function. Modern broiler breeders are feed restricted to limit the incidence of reproductive disorders and excessive body weight gain. A high degree of feed restriction is common during the pullet-phase, which has been identified as a welfare issue. This paper examines the productive and welfare implications of feed restriction in modern breeders and the implications of returning to ad libitum (AL) feeding conditions. Feed restricted hens are compared to AL fed hens to demonstrate the full range in potential results from eliminating or reducing the degree of feed restriction in broiler breeder management. Both full feeding and restricted feeding programmes impact bird welfare. The contrast of these methods is intended to provide background information for the development of a definition of what a normal or appropriate growth profile is for broiler breeders. The implications of overfeeding on the well-being of the birds make current feed restriction programmes the more welfare-friendly alternative, despite apparent drawbacks.