Barbosa Filho, 2005 – Egg Quality in Layers Housed in Different Production Systems and Submitted to Two Environmental Conditions

The production system using cages is a highly polemical issue in Europe, because of the space restriction imposed to laying hens. It is considered that the cage system might compromise important comfort movements, welfare and egg quality. This study evaluated egg quality and welfare of two strains of hens housed in a conventional system (battery laying cages) or litter system with nest and perches, and submitted to heat stress or comfort conditions. Two groups of 20 birds (10 Hy-line W36 and 10 Hy-line Brown) were submitted to two environmental conditions (26°C and 60% RH or 35°C and 70% RH) and two housing systems (cages or litter) in the early production phase. Egg quality was analyzed based on egg weight, eggshell thickness, specific gravity, and Haugh units. Yolk and shell contamination by Salmonella sp was also assessed. A significant (p<0.05) reduction in quality parameters was observed in eggs produced by laying hens under heat stress, mainly in the birds housed in cages.