Box rest - confinement to a stable for injury recovery - is one of the most welfare-challenging situations for horses, whose physiology and psychology are built around movement.
Box rest creates a profound mismatch between a horse's biological needs and its enforced environment. A horse confined to a 4x4 meter stable is unable to express virtually any of its normal behaviors - moving, grazing, social interaction, and exploration are all restricted or eliminated. Gastric ulcers develop rapidly in horses that stand still without continuous forage, as stomach acid attacks the squamous mucosa continuously. Stereotypic behaviors like crib-biting and weaving typically emerge or intensify during box rest as horses try to cope with boredom and frustration. Despite these costs, box rest is sometimes medically necessary - the welfare challenge is minimizing confinement duration and maximizing enrichment while protecting physical healing.