Horses are social animals evolved for continuous movement on open grassland — stabling without adequate turnout and social contact causes significant welfare problems documented by veterinary and behavioural science.
Horses stabled 24 hours per day without social contact develop crib-biting and weaving at significantly higher rates than those with turnout and social access. Stereotypies, once established, persist even when welfare conditions improve — prevention is more achievable than cure. Social isolation causes anxiety responses in horses including higher baseline cortisol and heightened reactivity. The Five Domains welfare assessment for horses emphasises social and behavioural needs as fundamental alongside nutrition and health. Performance horses may have legitimate medical reasons for restricted turnout, but welfare cost of confinement must be managed with compensatory social and environmental enrichment.