Comparison between Laying Hen Performance in the Cage System and the Deep Litter System on a Diet Free from Animal Protein

Abstract

Battery cage systems for housing laying hens are being replaced by alternative systems including the deep litter system. At the same time, the substitution of meat and bone meal by vegetable matter in poultry feed mixtures is sought in the nutrition of laying hens. In the experiment, we compared the performance of laying hens of the ISA BROWN hybrid in both the cage system and the deep litter system, on a diet with the meat and bone meal content replaced by vegetable feeds (based on lupin). In the first group, 36 laying hens were kept in the deep litter system; in the second group, 36 laying hens were kept in cages. Over the period of nine months, the number of eggs laid, their weight, shell quality, the clinical state of the laying hens and incidence of their mortality were monitored daily. We found that in the cage system a higher number of eggs was obtained; a lower mean egg weight (p < 0.01); a higher number of eggs per hen per day (p < 0.01); a higher egg mass weight per hen per day (p < 0.01). There was a higher number of cracked eggs of the total number of eggs laid (p < 0.01), the number of membranous eggs of the total number of eggs laid did not differ (p > 0.05), and the number of laying hens which died was lower (p < 0.05) in comparison with the deep litter system. The results of the experiment demonstrate that, with the substitution of meat and bone meal by vegetable matter in the feed mixtures for laying hens, there are differences between the performance of laying hens from the deep litter system as compared to the laying hens from the cage system. The deep litter system better meets the requirements for the welfare of laying hens; however, it provides a lower yield.