Q. Is it okay for a horse to live without herdmates or companions?
A. I am going to say that yes, it is okay for a horse to live alone, but with a bunch of caveats.
Horses are social animals. Feral horses live in harems, with a stallion, some mares, and offspring who will later disperse to other harems. Domesticated horses have lost really none of their "natural" behaviors. Nearly all of our domesticated species are highly social animals. That, along with their relative docility, probably contributed to them being good species for domestication.
So, having one or a few equine companions is probably better than living alone. Yet I have seen many horses living alone who seem fine. A glance at online bulletin boards show that many people keep a horse alone and don't perceive any problems. I do not know of any good long-term or survey-type research studies that identify specific widespread health or behavior problems in horses living completely alone for a long time. There are probably several keys to success. A horse with a temperament suitable to living alone is a good start. Then, I would try to meet all the other behavior needs: full time or majority time turnout, ad lib forages, and plenty of interactions with humans or even other animal species (goat or chicken buddies can work well).
To be sure, a horse living alone may develop problem behaviors. Studies have shown, not surprisingly, that horses taken from a group into an isolated environment for hours or days tend to show changes in stress hormones such as cortisol, and exhibit stress behaviors such as sweating, restlessness, and locomotory stereotypies like fence pacing.
Time budgets of horses taken into isolated conditions showed more time moving and less time eating. Horse management books always tell you that stereotypies are bound to occur with horses living in complete or partial isolation. Dr. Daniel Mills, professor of veterinary medicine behavior at Lincoln University in the United Kingdom, and his co-workers did some great research on weaving in horses kept in box stalls visually isolated from other horses. Weaving could be greatly reduced by placing a mirror in the stall. This suggested the importance of visual contact with other horses as well as an apparent benefit of a mirror to the horse. Conversely, University of Pennsylvania equine behaviorist Dr. Sue McDonnell's
observations of mares kept in tie stalls showed remarkably few stereotypies; however these mares had wide views of lots of other mares and majority time access to forages.
Horses have been selected and bred for behavior traits desirable for close human contact and for a variety of careers.Though we may strive to meet all of our horses' natural behavior needs, rarely do we achieve that. Being confined in stalls for any period of a day, limited feeding, frequently changing groupings at pasture, and forced exercise are all unnatural to the horse. Problems and risks related to keeping horses in groups, such as risk of injury or some horses denying others access to feed, are part of the reason we keep horses confined. It seems to me that horses have been able to handle a very wide variety of management schemes and isolation from other horses is just one of many. While it certainly is not optimal, if done thoughtfully, I believe keeping a horse alone is acceptable.
About the Author
Prior to attending veterinary school, Dr. Nancy Diehl completed a master’s degree in animal science while studying stallion sexual behavior. Later, she completed a residency in large animal internal medicine at the University of Pennsylvania’s New Bolton Center and worked in equine practices in Missouri and Pennsylvania. Diehl also spent six years on faculty at Penn State, where she taught equine science and behavior courses and advised graduate students completing equine behavior research. Additionally, Diehl has co-authored scientific papers on stallion behavior, early intensive handling of foals, and feral horse contraception. Currently she is a practicing veterinarian in central Pennsylvania.