Weaving is a stable vice of horses, in which the horse repetitively sways side to side, shifting weight and moving its head and neck back and forth.
Horses often perform this vice over a stall door, or near the grill of the stall, possibly because it is the exit from the stall, or because their view changes slightly as they view the barn aisle from the stall and is visually stimulating. Some horses that have developed the habit will also weave while turned out. Although it is commonly thought that weaving is caused by boredom, many experts consider it a stress response, usually due to isolation from other horses, unhappiness in general, or little grazing time.
Many horsemen believe weaving is a learned habit. However, some experts theorize that weaving could be more likely to develop in horses with a genetic predisposition. Thus there is debate over whether weaving is a learned behavior that other horses can pick up by observing another, or if it is an inborn tendency that develops under a certain set of environmental conditions. Therefore, some people claim it is usually safe to allow other horses to see a weaver, unless it is known that they are genetically predisposed (their sire or dam was a weaver). Others feel it is caused by environmental factors, and that other horses in the same setting will pick up the behavior once a single horse starts.
Weaving is generally not a very damaging vice in the short term. However, horses that are constant weavers over time may have abnormal hoof wear, and slowly stress their joints. The stall floor may also come to have uneven wear. However, overall the value of a weaving horse is not necessarily diminished by this condition.
Like most vices, weaving is a very difficult habit to break. However, there are several ways to manage a weaver: