Comparison of egg production, quality and composition in three production systems for laying hens

Abstract

The increasing public concern for animal welfare has pushed the poultry sector to progressively replace conventional battery cages (CC) for laying hens with alternative systems such as enriched cages (EC) and aviaries (AV). The aim of this study was to compare laying performance, egg location, and egg quality associated with these three housing types. The experiment was conducted in twelve pilot-scale chambers fitted out with one of the three treatments. Each chamber housed 30 Lohmann LSL-Lite laying hens from 23 to 32 weeks of age. The available area was 492, 780, and 1120 cm²/hen for CC, EC, and AV, respectively. The EC and AV chambers were equipped with nest boxes, perches, and a pecking/scratching area (PSA). In the AV chambers, hens had free access to a space arranged in three levels with a wood shaving litter on the ground level as a PSA. Hen-day production was recorded and egg quality assessment included egg cleanliness, weight and proportion of each component (albumen, yolk, and shell) but also pH, Haugh unit, and meat spots for albumen; color intensity and blood spots for yolk; thickness and resistance for shell. The laying rate and egg weight were similar for CC and EC (around 96.5% and 59.5 g; P > 0.05). For AV, these parameters were significantly lower (77.2% and 58.6 g; P < 0.001) but the differences compared to the cage systems progressively reduced across time. Nearby 70% of the eggs were laid in the nests with EC while almost all of the eggs were laid on the litter at ground level with AV. The rate of clean eggs was around 77% for both cage systems compared to 14% for AV. Most of egg quality traits were identical for the three systems (P > 0.05) but there was a lower yolk proportion for eggs laid in AV (25.2% versus 25.7% for cages systems; P < 0.001) and higher shell resistance for eggs laid in CC (40.7 N versus 39.3 N for alternative systems; P < 0.001). Lower laying performance observed with AV could be explained by higher animal activity and competition for facilities, but these factors were not measured in this study. The reduction of the difference in egg productivity over time compared to cage systems suggest the need for a period of training/adaptation for pullets/hens kept in such an environment. An enriched cage system seems a balanced solution that combines both laying productivity and improved animal welfare. Further research should be performed to improve acceptance and appropriate use of resources by birds in an aviary system.