Box walking, stall circling and weaving are examples of locomotor stereotypic behaviours in horses. They are believed to be caused by a lack of freedom to express natural equine behaviours.
Over time, stall walking and weaving can have negative physical consequences such as hoof problems, joint wear and tear, weight loss, ulcers, and uneven muscle development. 
Stereotypic behaviours are repetitive, habitual movement patterns with no obvious function or benefit to the animal.  These behaviours are often seen in confined or domesticated horses that do not have access to the same lifestyle as their wild counterparts.
Stall walking, circling and weaving are common and difficult to stop completely. However, changes in management and routine can reduce a horse’s compulsion to perform these actions.
Increasing turnout, feeding a forage-based diet, providing a buddy for your horse, combatting stress and avoiding known triggers can reduce the severity and frequency of the behaviours.
Stereotypic Behaviours in Horses
Weaving, stall walking and circling are undesirable, repetitive behaviours, which horses commonly exhibit when confined, frustrated, bored or stressed.
Stereotypic behaviours are rarely seen in wild horses, but an estimated 10 – 40% of stabled horses exhibit some form of stereotypy. 
Other examples of stereotypic behaviours include: 
- Cribbing and windsucking
- Wood chewing
- Stall kicking
- Repetitive licking or mouthing
- Repetitive head movements
- Fence pacing
Some horses express one of these behaviours while other horses express multiple stereotypies.
These behaviours can be divided into locomotor stereotypies (i.e. box walking, circling or weaving) and oral stereotypies (i.e. cribbing or wood chewing).
Most stereotypic behaviours develop because of stressful environmental conditions, such as extended periods of confinement or a lack of forage in the diet.  Personality, genetics and nervous system dysfunction can also play a role. 
Horses do not consciously choose to perform stereotypic behaviours. These behaviours are automatic responses or coping mechanisms to help the horse alleviate feelings of distress. 
Stall Walking, Circling and Weaving
Stall walking or stall circling occurs when a horse circles or paces back and forth in their stall or another small confined area.
Sometimes the horse may circle once or twice then settle to eat. Other times the horse may circle frantically for extended periods, only pausing to grab bites of hay.
Stall weaving is characterized by a horse swaying their head and neck from side to side and shifting weight between their front feet. The behaviour is usually performed next to an escape area, such as the door to their stall or a gate exiting their paddock.
Mild versions of weaving involve the horse gently moving their head and neck back and forth. In more severe cases, the horse may horse violently shift their body weight completely onto one foot and then the other.
Stall weaving and walking are annoying habits, potentially contributing to messy stalls or wear and tear on your horse’s stable. If left unaddressed, these behaviours could also seriously impact the psychological and physical well-being of the horse.
Stall walking and weaving may result from psychological stress and anticipation of feeding time or turnout. 
These impulsive self-soothing behaviours may develop due to sub-optimal environments, feeding, care conditions, boredom or a lack of activity. Stall walking, circling and weaving are associated with limited turnout, long periods of confinement and social isolation.
Horses that express locomotor stereotypies are generally more stressed and have a nervous disposition. Some of this may be attributed to genetic differences, neurology or personality traits, but other factors are attributed to lifestyle and management.
If your horse is stall walking or weaving, it’s a sign that something in their daily routine needs to change to support a lower stress level.
Short-term stall walking or weaving episodes are fairly common and unlikely to have long-lasting negative effects on your horse’s welfare.
However, the repetitive nature of these movements could increase susceptibility to some physical ailments if your horse performs these behaviours for longer periods.
The AAEP notes that research into the negative consequences of stall walking and weaving is limited, and it’s unclear whether the behaviours lead to harmful outcomes. 
However, it has been proposed that the repetitive back-and-forth weaving motion could cause abnormal joint and hoof wear and muscle development in the front limbs. Stall circling can also affect athletic performance. 
Hoof, Joint & Muscle Issues
Horses are naturally built to walk forwards and backward, rather than move side to side. In horses exhibiting stall weaving, the muscles that bring the front legs out and in (abductors and adductors) can develop abnormally, causing stiffness. 
Horses that stall walk will often circle in only one direction. This can cause imbalanced muscle development, as well as hoof and joint wear on one side.
Imagine a person strength training only one side of the body. The muscles on that side of the body grow while others remain underdeveloped. 
In extreme cases, stall-walking horses can develop arthritis of the neck and back, due to the near-constant bending action of the spine while circling.
Excess strain on these joints can cause inflammation and deterioration of cartilage, leading to arthritis and abnormal bone growth. 
Horses that experience high levels of stress will often forgo eating their hay or grain to perform stereotypic behaviours. This can result in lower food intake and contribute to a negative energy balance. 
In some cases, gastric ulcers are believed to contribute to stereotypical behaviour.  In other cases, stereotypies are believed to contribute to the formation of ulcers, or both are believed to arise from a common cause.
Horses that stall walk or weave tend to have higher stress levels – a known risk factor for ulcers.  Stall walking and weaving can also influence appetite and interfere with foraging behaviour, potentially leading to ulcers.
Causes of Stall Walking and Weaving
Stall circling and weaving are similar behaviours that arise from many of the same causes, including stress due to confinement, genetic pre-disposition, and nervous system dysfunction.
Isolation and Confinement
Long periods of solitary confinement in a stall can contribute to stall walking or weaving, especially if your horse is stabled so that they cannot see or touch other horses. 
Horses are herd animals that evolved to live in large, stable social groupings with constant access to members of their own species. Most horses experience stress when separated from other horses for even brief periods.
In one study, stress markers were significantly higher in horses isolated and confined to stalls compared to horses turned out in paddocks. This study measured cortisol levels and the ratio of neutrophils to lymphocytes in horses, both reliable stress markers. 
Lack of Turnout
Locomotor stereotypies are also improved when turnout increases, suggesting that a lack of turnout can contribute