The Influence of Density and a Partially Shadowed Layer on the Behaviour and Welfare of Broiler Breeders in Battery Cages During Laying

This study compared the behavioural differences of broiler breeders reared under two different densities (Singly-caged: 1 600 cm² per hen; Paired: 800 cm² per hen), and in shadowed cages with a half-covering layer on their tops versus controls in order to evaluate the laying preferences of the species in dark versus light regions. The results showed that singly-caged broiler breeders displayed turn-around and head-scratch behaviours more than paired breeders, while singly-caged breeders presented wing-flap behaviours less than paired breeders. Single and paired breeders spent both more time eating in cages which were partially covered than those in control cages. Singly-caged breeders were more likely to lay in the dark region in shadowed cages than paired breeders. These results suggested that broiler breeders exhibited normal behaviours more often when raised in a larger living space and in shadowed cages. Although stocking density has more impact on behaviour and welfare for broiler layers than light environment, being shadowed can reduce overcrowding effect and may alleviate the worse welfare appearance for caged broiler breeders.

Keywords
Broiler breeder; Battery cage; Stocking density; Shadowed layer; Environmental enrichment; Animal behaviour and welfare