Horses evolved as continuous grazers, spending 16-18 hours daily eating grass, and restriction of grazing through stabling and restricted turnout causes both behavioral and physiological welfare problems that pasture access largely prevents.
Restriction of grazing is one of the most widespread and significant welfare compromises for domestic horses. The equine digestive system, evolved for continuous low-intake forage consumption, is physiologically stressed by infrequent large meals - the standard feeding regime in many stables. Gastric ulcers are almost universal in horses with limited forage access, causing chronic pain that affects behavior, performance, and welfare. Stereotypic behaviors that develop from restricted turnout are neurologically fixed and persist even when conditions improve, demonstrating lasting damage from early deprivation. Maximizing turnout time and forage access is the single most effective welfare intervention for most domestic horses.