In modern stable designs, horses are often housed and turned out individually for fear that they will injure one another. But solitary confinement is just as hard on horses as it is on people. In fact, horses are evolutionarily designed to avoid confrontation and embrace affiliation in order to reap the most benefit from living within a group.

For animals living in stable social organizations, behaviours that avoid conflict rather than escalate it are adaptive and become propagated through evolution. An aggressor expends energy resources, risks serious injury, and may forfeit the advantages of group membership if he becomes ostracized from the herd. Aggression may have equally dire consequences for the winners by threatening group cohesion and jeopardizing future cooperation.

In the grand scheme of herd living, serious aggression seldom reaps a benefit that outweighs its cost. However, some planning must go into introducing unfamiliar horses into established social groups and ensuring harmony in the herd.

Turn Out Tips

Pre-Exposure Reduces Conflict
Researchers have reported that as little as five minutes of tactile contact (i.e. letting horses smell, touch, squeal and carry on) in adjacent stalls or paddocks before being turned out together all but eliminates aggressive encounters. Although pre-exposure encounters can sound horrific, horses generally engage in non-contact “ritualistic behaviours,” that substitute for actual aggression.

Keep Groups Consistent
A key to maintaining safe herd dynamics is to avoid making changes where possible. New additions and even new subtractions force the herd to reestablish hierarchies and create greater potential for positions to be challenged, thus elevating the risk of injury.

Remove Hind Shoes
When setting up groups initially, or if groups must be changed, removing hind shoes can reduce injury while negotiations are being sorted out. Once challenges have been reconciled (generally within two or three days) the shoes can be replaced if necessary.

Provide Plentiful Resources
When environments are rich with resources, particularly edible resources, psychological well-being flourishes, and aggression is reduced. The provision of multiple widely dispersed watering sources, several shelter alternatives, numerous scratching stations, access to free-choice hay at multiple stations and/or plentiful pasture, makes arguments over resources a non-starter. Ensure there is ample distance between feeding stations and provide more stations than horses. For horses that are prone to obesity, consider a grazing muzzle rather than restricting hay for the whole group.

Mixed Groups are Preferable
Mixed groups of mares and geldings are no more aggressive than segregated gender groups. Some studies suggest that more threatening behaviours occur in groups with less variability in gender, size and age. It seems that in mixed groups, horses learn all aspects of social communication, can more readily find a compatible partner, and can more easily avoid those who are not congenial.

Stallion Groups Work Too
Even the belief that stallions must be singly housed has been challenged. At the Swiss National Stud, Sabrina Briefer-Freymond’s research group successfully pastured five to eight elite (and expensive!) breeding stallions together during their non-breeding season. Stallions were housed in large pastures away from mares, had multiple feeding stations, met in adjacent stalls before group turn out, and hind shoes were removed before the initial encounter. Groups remained stable throughout the season. Rather than fighting, the stallions engaged in non-contact ritualistic behaviours. There were no injuries, psychological well-being improved, and management costs were greatly reduced. The study was so successful that the Swiss National Stud continues to pasture this “bachelor band” every year.

Solitary Turn Out Solutions
If group turn out is not feasible in your situation, an effort should be made to let horses touch and see each other.

Eliminating electric wire between paddocks, installing grilled windows, half walls, or half wood/half grill walls between stalls will permit horses to socialize with little danger of injury. A study of chronic weavers found that weaving was completely eliminated when horses were housed in stalls that were open on all sides, allowing them to interact with neighbours.

As a third best alternative, providing an open-fronted stall increases horses’ visual contact with neighbours. Many modern stall designs incorporate U-shaped stall fronts that, while an improvement over solid fronts in providing greater visibility, are too high to allow horses to hang their heads in a relaxed position. Commercial, rubber or webbing stall guards allow horses to relax with the head below the withers, are inexpensive, and the height can be individualized for each horse. All but the most rambunctious horses quickly learn to respect this barrier.