Incubation temperature profiles affect broiler feathering

Abstract

Two experiments were conducted to assess the effects of incubation temperature profiles, breeder feed restriction programs, and litter conditions on progeny feather follicle (FF) density and skin layer thickness. In the first experiment, Cobb 500 fast feathering breeders were subjected to 2 feed restriction programs during rearing: skip-a-day (SAD) and every-day feeding (EDF). Eggs from each group were incubated according to 2 incubation temperature profiles: standard (S) and early-low late-high (LH). A total of 72 chicks per treatment combination were placed in Petersime cages (6/cage) and sampled for skin in the breast, dorsum, and thigh areas at 22 d. Additional samples were collected from the thigh and measured for epidermal and dermal thickness. For the second experiment, 2,475 eggs from a commercial flock of Cobb 500 fast feathering breeders were subjected to 3 incubation temperature profiles: S, LH, and standard-high (SH). At hatch, 1,260 chickens were placed in floor pens (14/pen) that contained either used litter or new wood shavings. At 28 d of age, 2 chickens per pen were sampled for skin in the breast, dorsum, and thigh areas. In both experiments, FF were counted in 4.5 cm2. It was concluded that incubation temperature affected feathering development in both experiments, especially in the breast. This effect may be stronger in progeny from breeders restricted under SAD programs. Moreover, litter conditions impacted FF numbers. These findings may be applied to minimize carcass scratches and improve broiler welfare.