How to prevent (or deal with) the ‘vices’ now known as stereotypies.
Stereotypies (once called stable vices) are repetitive behaviors that serve no discernible purpose. They include cribbing and windsucking, weaving, stall- and fence-walking, and self-mutilation. They begin when horses attempt to relieve the stress caused by negative environmental factors—such as confinement, isolation, sweet feeds that cause gastric distress, etc. To prevent stereotypies from developing or to minimize their expression, attend to your horse’s behavioral needs (see below). Also avoid high-carb feeds in favor of pasture grazing or low-calorie grass hay fed in amounts to keep your horse busy with extra “chew time.”
Stall confinement—especially in the absence of hay or straw to chew on—increases the risk of stereotypies.