The transition from battery cages to enriched colony cages represented a welfare improvement, but free-range and barn systems provide substantially better welfare outcomes for laying hens.
The welfare gradient from enriched colony to barn to free-range reflects the ability of hens to express natural behaviours. Hens in enriched colonies cannot fully extend their wings, cannot dust bathe properly in the provided scratch area, and experience chronic frustration of their foraging motivation in a barren cage environment. Free-range hens can perform the full repertoire of natural behaviours including foraging, dust bathing, and exploring outdoor environments. The welfare gap between the systems is significant and well-evidenced. Consumer purchasing decisions directly drive the proportion of eggs produced under different welfare standards — the shift from cage to free-range egg purchasing in UK supermarkets has produced a measurable improvement in the proportion of hens kept in better conditions.