How herd social structure affects horse stress and welfare in managed environments.
Horse welfare in managed environments depends substantially on social management — who horses live with, how stable those relationships are, and how much contact with other horses they can maintain. Horses evolved in stable social groups, and their stress regulatory systems reflect this: social companions provide emotional buffer against environmental stressors. Management systems that frequently shuffle horses between groups, maintain horses in isolation, or allow only brief daily contact with other horses impose social stress that compounds any other welfare pressures. Even horses that cannot be safely kept together benefit from visual and olfactory contact across a fence — the social presence of other horses reduces isolation distress significantly. Stable herd membership is a welfare resource worth protecting.