Floor versus cage rearing: effects on production, egg quality and physical condition of laying hens housed in furnished cages

摘要

The influences of floor- and cage-rearing on egg production, egg quality and physical condition were investigated in laying hens housed in furnished cages. Two groups of 180 Isa Brown commercial layer pullets were reared in cages (CR) or floor pens (FR) and transferred to furnished cages, where their production, egg quality and physical condition was observed throughout the laying period (18-78wks of age). At 17 weeks of age, hens were placed in one of 36 furnished cages with 10 birds in each cage, each containing a nest box, perches, a dust bath, and abrasive strips. From 19 to 78 weeks of age, egg production data were collected daily. Commercial egg quality was assessed monthly. At, 19 and 78 weeks of age, claw length and feather cover were visually assessed using a four-point scale in a sample (10%) of hens. Production variables were above breeders’ standards and not significantly affected by rearing system. Dirty eggs and cracked eggs were more frequent in FR birds. Meat spots were significantly more frequent in FR hens at middle lay, but less frequently at the end of the laying period. Rearing system did not influence egg and yolk weight or unit Haugh and shell colour. Among FR hens, eggshell density, thickness and mass were significantly lower at the end of the laying period. Rearing system did not affect claw length, but the plumage of FR hens was negatively affected at the end of production cycle.