Aviary housing systems allow laying hens to express more natural behaviors than conventional or enriched cages, but their welfare benefits depend critically on how they are designed and managed, and they present distinct challenges including keel bone fractures and air quality.
Aviary systems represent genuine welfare progress over conventional cages — hens can walk, perch, spread their wings, and express a wider range of natural behaviors. However, they are far from a welfare solution in themselves. The high prevalence of keel bone fractures in aviary systems is a serious welfare concern that the industry is only beginning to address. Poor air quality, inadequate management, and overcrowding can make some aviary systems no better — and sometimes worse — than enriched cages in terms of measurable welfare outcomes. The best aviary systems, managed by skilled, welfare-conscious producers, can offer genuinely good lives for hens. The worst can be chaotic and harmful. The difference lies almost entirely in management and design quality.