Many laying hen companies in the United States are pledging to move away from intensive conventional cages to extensive housing systems. Enriched colony cages (ECC) are a practical alternative to conventional cage systems. Scientific research is limited on the effects of ECC on hen production and welfare. Therefore, the objective of this study was to evaluate the effects of stocking density on welfare and performance with the overall outcome to provide guidance on stocking density for ECC. At 16 wk, W-36 pullets were placed into 2 commercial ECC housing systems. Within each ECC enclosure, hens were allocated into 1 of 6 stocking densities: A) 465 to 484 cm2/bird, B) 581 to 606 cm2/bird, C) 652 to 677 cm2/bird, D) 754 to 780 cm2/bird, E) 799 to 832 cm2/bird, and F) 923 to 955 cm2/bird. Body weight, egg production, mortality, and Welfare Quality data were collected each 28 d period from 17 to 68 wk. The 6 ECC stocking densities had several transient effects on production measures within age periods with no difference in hen-day production (P > 0.05). Body weight was affected by stocking density (P < 0.05) where hens raised at stocking density A (465 to 484 cm2/bird) weighed at least 25 g less than hens from other stocking densities. Stocking density differences for Welfare Quality assessments were only apparent for feather coverage. Hens raised at stocking density A (465 to 484 cm2) consistently had the poorest (P < 0.05) crop, keel, belly, back, and rump feather coverage. The keel, neck, and back body regions had poorer feather coverage when hens were raised at stocking densities B (581 to 606 cm2) and C (652 to 677 cm2) compared to hens from lower stocking densities (P < 0.05). Therefore, the minimum area per hen housed in commercial ECC systems should be 754 cm2 per bird for greater feather coverage.
Keywords: enriched colony cage; laying hen; stocking density; welfare.
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