Laying hens welfare evaluation: effects of rearing system and bioclimatic environment on performance and egg quality

This work aimed to evaluate the effect of two different rearing systems ( cages and litter) on productive performance and egg quality of laying hens. The trial was conducted for five experimental periods of 28 days each. Sixty four pullets of the laying strain Isabrown and 64 pullets of the laying strain Hy-Line W-36, with ages of 19 and 21 weeks, respectively, were used. The combination of two rearing systems ( conventional cages and floor system with litter) and two layer strains was evaluated using a completely randomized design, with a 2 x 2 factorial arrangement, and four replicates. The thermal evaluation was performed by analysis of dry air and black globe temperature and relative humidity. For the productive performance analysis, egg production and feed conversion ratio were evaluated. For the egg quality analysis, egg weight, Haugh unit, specific gravity, integrity, clearness and shell thickness were evaluated. No differences on the productive performance between rearing systems were observed. The floor system, when properly projected, can be comparable to the cage system with respect to the productive performance and the egg quality. Moreover, this rearing system could provided better results for egg quality with lesser egg losses although in less favorable thermal comfort conditions. However, mainly for the semi heavy strain, it could result in larger dirty egg percentage.