Stereotypic behaviors, more commonly known as “stable vices,” in horses are repetitive and seemingly functionless behaviors. They can be divided into two general categories: locomotor (i.e. stall weaving, circling, kicking), and oral (cribbing, wind sucking, wood chewing). Stereotypic behaviors may be associated with health issues such as hoof damage (stall kicking) and tooth erosion (cribbing) or even colic (however, contrary to popular belief, cribbing horses do not actually swallow air).
Stereotypies rarely can be traced to a single cause; they generally are associated with a variety of factors, most of which are management related. However, genetic and medical problems also predispose horses to develop certain stereotypies.
Stable vices frequently occur to allow the horse to cope with an inadequate environment. Locomotor stereotypies are typically associated with insufficient contact with other horses, too limited turnout, and other “physical” restrictions. Oral stereotypies are most likely to be related to foraging frustration (e.g. too little roughage, limited grazing time, too much grain/starch in the diet, etc.).
Although people suspect mimicry is involved and often isolate horses with stereotypic behaviors, there is no evidence that horses can learn these behaviors by watching other horses perform them. Some stable vices are learned through inadvertent reinforcement by owners and barn managers. For example if a horse begins kicking or circling in the stall before meal time, the subsequent delivery of the horse’s food will reinforce the behavior.
Stable vices can be frustrating and difficult to remedy. The behaviors sometimes persist even when the apparent cause of the behavior is remedied. Physically preventing the horse from performing the behavior is problematic in that it does nothing to remove the motivation for the behavior. This approach seldom works and it may cause the animal more distress because the horse is prevented from using its only coping strategy in that environment.
Environmental enrichment is a good way to improve the horse’s management and hopefully discourage some of these behaviors. General recommendations for locomotor stereotypies include increasing turnout and exercise, and providing social contact. Recent studies have shown that installing mirrors or a life-sized picture of a horse in the stall can reduce weaving and other locomotor stereotypies. Oral stereotypies may be prevented or improved by increasing forage, allowing more grazing time and reducing grain/starch in the diet. Many stereotypies can also be remedied by behavior modification techniques designed to teach the horse to perform an alternative, more desirable, behavior in that situation. This method has the added benefit of providing the horse with additional behavioral choices as opposed to removing or limiting the horse’s choices.
More specific training, housing and medical recommendations are determined on a case-by case basis. Due to the complexity and medical implications of stereotypic behaviors, consulting a veterinarian is highly recommended to find resolutions for the horse’s behavior.