Horses are highly social animals that suffer when isolated from conspecifics, with significant welfare consequences for horses kept alone.
Horse isolation is a profound and widespread welfare problem that receives insufficient attention. Horses evolved in social groups and maintain complex relationships including mutual grooming, synchronized behavior, and emotional support. A horse kept alone experiences chronic social deprivation even when it has adequate space, food, and exercise. The stress of isolation contributes to difficult behaviors like stable vices, sensitivity to handling, and reactivity that creates safety risks for handlers. The welfare improvement from providing appropriate social contact - even visual contact with other horses - is substantial. Single-horse ownership should include consideration of how social needs will be met.