THE EFFECT OF LONG-TERM HOUSING IN AN AVIARY AND BATTERY CAGES ON THE PHYSICAL CONDITION OF LAYING HENS - BODY-WEIGHT, FEATHER CONDITION, CLAW LENGTH, FOOT LESIONS, AND TIBIA STRENGTH

The physical condition of laying hens housed for 3 yr in either traditional battery cages or an aviary was compared. Aviary hens were significantly lighter than those in cages (2,021 vs 2241 g; P = .0001), despite having consumed slightly more feed (121 vs 116 g per bird per d, P = .16). Caged hens had poorer feather cover (P = .0001); 39% of caged birds had denuded areas greater than 5 cm(2),whereas 68% of aviary hens had complete plumage. The length of both center front and rear claws was significantly greater in caged hens (36.3 vs 30.3 mm, P = .001 and 19.2 vs 16.1 mm, P = .012 respectively). The total number of foot lesions did not differ with housing system; however, caged hens had significantly more toe injuries (P < .001), and aviary birds had more injuries on the soles of their feet (P = .005). All aviary birds with foot lesions had only a single lesion, whereas one-sixth of caged hens with lesions had more than one. No difference in tibial breaking strength was found due to housing system. Overall, the results suggest that aviary systems can offer some distinct advantages over traditional battery cages with regard to the physical condition of laying hens, given a high level of management.