Horses are highly social herd animals that suffer significantly from isolation; providing species-appropriate companionship is one of the most important aspects of equine welfare.
Horse welfare depends on social contact with conspecifics (or appropriate substitutes) in a way that is often underestimated by owners who focus on physical care. Horses evolved as prey animals that gain both psychological security and physiological benefit from group membership. Isolation - whether in a stable without visual contact or a paddock without equine companions - causes demonstrable stress responses. The welfare case for equine companionship is strong enough that it is now enshrined in UK welfare legislation. Meeting this need is typically achievable and should be considered a basic requirement rather than an optional luxury.