The barren battery cage
Barren battery cages (which are now illegal in the EU) typically hold 4 or 5 hens with low space allowance. Previously, the EU permitted a minimum floor space of 550cm2/hen, which is smaller than the area of an A4 sheet of paper. Sadly, space allowance per hen is even lower in many other countries. The cage is bare except for the provision of feed and water and has a sloping, wire mesh floor on which the hens live and lay their eggs. There is no nest where they can lay their eggs and no opportunity for them to express natural behaviours such as spreading their wings, walking, scratching or perching.
The enriched cage
Enriched cages in the EU must provide a legal minimum floor space of 750cm2 per hen (600cm2 of which has to be “usable”).Group size is variable, and the hens are provided with a small perch, litter and a nest. The enriched cage therefore provides hens with slightly more space and the opportunity to perform some of their natural behaviours to a very limited extent. However, the enriched cage is considered unacceptable; it is still a confinement system and still restricts behaviour.
Commonly, caged systems (both barren and enriched) house many tens of thousands of hens in closed sheds, with the cages stacked in many rows and tiers. Ventilation is fan driven and the sheds are dimly lit to reduce activity and aggression; the hens do not experience natural daylight or day length changes.