The global shift away from battery cages and the welfare evidence driving it
The global layer hen industry is undergoing the most significant housing transition in its history. Battery cages — which confine hens in spaces smaller than an A4 sheet of paper — have been banned in the EU since 2012, and cage-free commitments from retailers, food companies, and governments are driving rapid change worldwide. This page reviews the welfare evidence underpinning these transitions and examines the relative merits of different housing systems.
Conventional battery cages (banned EU, California, some states): Lowest welfare. Unable to express any natural behavior. High bone fragility. High rates of feather loss from frustration and cage rubbing.
Enriched/furnished cages: EU standard. Provides nest box, perch, scratch area. Significant welfare improvement but still restricts natural behavior substantially. Keel bone fracture rate still high (~50%).
Cage-free barn systems: No cages; floor-based with litter, nest boxes, perches. Better welfare than any cage system. Challenges: ammonia management, disease transmission, dustiness, mortality from injurious pecking.
Aviary systems: Multi-tier structures with perches, nest boxes, litter, and aerial access. Best welfare outcomes of commercial systems. Higher infrastructure cost but consistently better bone health, behavioral diversity, and positive welfare indicators.
The cage-free transition faces real challenges: capital costs for retrofitting buildings, management complexity, increased mortality risk from injurious pecking if management is poor, and disease management in higher-density floor housing. Research programs in the US (Coalition for Sustainable Egg Supply), EU (LayWel project), and Australia are developing evidence-based management protocols to address these challenges and enable welfare benefits to be reliably achieved.