Horses are social animals that evolved in herd groups. Isolation - whether from stabling, single-horse keeping or separation from companions - causes significant, measurable welfare harm.
Horse social isolation is one of the most common yet least acknowledged welfare failures in companion horse keeping. The single horse in a small paddock with only occasional human contact is not fulfilling a wild, independent lifestyle - it is experiencing chronic social deprivation in an animal whose nervous system evolved for constant herd membership. Stabling compounds isolation: a horse in a stable cannot even maintain the visual and olfactory contact with other horses that provides partial social satisfaction. The solution is straightforward: horses should be kept with other horses, ideally with physical contact, and stabling should be minimised. This requires changing cultural norms around horse keeping that prioritise owner convenience over horse welfare.