|WEIMER, SHAWNA - Purdue University|
|ROBISON, CARA - Michigan State University|
|TEMPELMAN, ROBERT - Michigan State University|
|KARCHER, DARRIN - Purdue University|
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/22/2019
Publication Date: 9/1/2019
Citation: Weimer, S.L., Robison, C.I., Tempelman, R.J., Jones, D.R., Karcher, D.M. 2019. Laying hen production and welfare in enriched colony cages at different stocking densities. Poultry Science. 98:3578-3586.
Interpretive Summary: In the past decade, egg producers have faced pressure and scrutiny to change the way in which laying hens are housed, primarily from a welfare concern standpoint. The laying hen industry is moving away from conventional cages to housing systems deemed more welfare-friendly. However, literature reviews have established that all housing systems have their advantages and disadvantages for hen production, health, and welfare. Enriched colony cages (ECC), often referred to as ‘furnished cages’, are a practical alternative to conventional cage systems, offering more space per bird, perches, nest boxes and scratch pads. Stocking density is the space allowance for an individual bird. Providing more space relative to a hen’s body area will increase their freedom of movement. Research is necessary to establish the optimal stocking density range in which laying hens should be housed in ECC systems. The six ECC stocking densities evaluated in this study had a transient, inconsistent effect on laying hen production measures. However, hens stocked at 652 – 677 cm2/hen had feather coverage better than hens housed at densities less than 606 cm2/hen. Therefore, the minimum area per hen housed in commercial ECC systems should be 652 cm2 per bird.
Technical Abstract: 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 two commercial ECC housing systems. Within each ECC enclosure, hens were allocated into one of six stocking densities: A) 465 - 484 cm2/bird, B) 581 - 606 cm2/bird, C) 652 - 677 cm2/bird, D) 754 - 780 cm2/bird, E) 799 - 832 cm2/bird, and F) 923 - 955 cm2/bird. Body weight, egg production, mortality and Welfare Quality® data were collected each 28 d period from 17 to 68 wk. The six 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 - 484 cm2/bird) weighed at least 25 g less than other stocking densities. Stocking density differences for Welfare Quality® assessments were only apparent for feather coverage. Hens raised at stocking density A (465 - 484 cm2) consistently had the least (P < 0.05) head, crop, keel, back, rump and belly feather coverage. The neck, keel, and back body regions had less feather coverage when hens were raised at stocking densities B (581-606 cm2) and C (652-677 cm2) compared to lower stocking densities (P < 0.05). Therefore, hens housed at high stocking densities in ECC systems may have reduced welfare and a minimum stocking density of 652 cm2 per bird is suggested.