Effects of ambient temperature, plumage condition, and housing system on energy partitioning and performance in laying hens

Environmental factors, e.g. temperature (T), feather cover (FC), and housing system (HS) affect energy requirements of laying hens. Interaction effects of T (11°C, 16°C, 21°C), FC (100% vs. 50%) and HS (cage vs. floor) on energy partitioning and performance of laying hens were investigated. Six batches of 70 brown layers per batch were applied. Heat production (HP) was determined by indirect calorimetry. ME-intake increased by 1% for each degree reduction in T. HP was not affected by T in hens with 100% FC, whereas in hens with 50% FC HP linearly increased if T decreased. In floor housing, HP at 16°C and 11°C was 5.8% and 3.0% higher, respectively, than in cages. NE for production (NEp) was 25.7% higher in cages compared to floor housing. In cages, 24.7% of NEp was spent on body fat deposition, whereas in floor housing 9.0% of NEp was released from body fat reserves. ME-intake (kJ/d) was predicted by: 586 BW0.75 – 7.94 T + 26.84 Daily gain + 11.36 Egg mass – 0.993 FC – 36.2 HS (0 = cages, 1 = floor; R2 = 0.75). Despite considerable differences among treatments, egg performances were not affected, indicating the adaptive capacity of layers to a broad range of environmental conditions