The barren battery cage:

In the EU, barren battery cages typically hold 4 or 5 hens at the legal minimum floor space of 550cm2/hen. This is smaller than the area of an ordinary A4 sheet of typing paper (620cm2). Sadly, in the USA, space allowance per hen is typically even lower. 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 to lay their eggs and no opportunity to spread their wings, walk more than a few steps, scratch or perch.

The enriched cage:

Enriched cages provide a legal minimum floor space of 750cm2 of space 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. Whilst providing hens with slightly more space and the opportunity to perform some of their natural behaviours to a limited extent, 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 dim lit to reduce activity and aggression; the hens do not experience natural daylight or day length changes.