Horses are highly social animals that evolved in herd environments, and isolation — a common feature of modern horse management — causes significant psychological stress with measurable physiological and behavioral consequences.
The individual stall is an unnatural and psychologically challenging environment for horses, who evolved constant social contact with herd members. Horses in individual stalls develop stereotypic behaviors — cribbing, weaving, stall walking — at far higher rates than pasture-kept horses, reflecting the psychological cost of isolation and movement restriction. The motivation to be near other horses is so strong that stall-kept horses show cardiac stress responses to the sounds of other horses in distress and seek visual contact with neighbors compulsively. Management systems allowing group turnout, even for a few hours daily, significantly reduce behavioral indicators of psychological distress. The economic and management convenience of individual stalling has consistently been prioritized over the welfare costs to the animals.