Gestation crates are metal stalls that confine pregnant sows so tightly they cannot turn around, causing severe behavioral deprivation, muscle atrophy, and psychological distress that animal welfare scientists consider among the worst welfare problems in modern agriculture.
Gestation crates impose near-total behavioral restriction on sows for virtually their entire productive lives. A sow can spend years unable to walk, turn around, or engage in any natural behavior beyond standing and lying. The psychological costs are demonstrated by the high prevalence of stereotypic behaviors — repetitive purposeless movements like rooting the crate floor or bar-biting that indicate the animal is coping with an environment that cannot meet her behavioral needs. The existence of functional group housing systems in the EU demonstrates that gestation crate elimination is commercially viable, making continued use in the US primarily an economic rather than a technical necessity.