Weaving in Horses: Causes, Effects & How to Prevent

Weaving is a locomotive stereotypic behaviour typically seen in stabled horses. It is estimated that between 3 to 10% of horses kept in stables weave. ^[1]

The expression of this behaviour involves repetitive shifting of body weight from one front leg to the other, combined with a sideways swaying of the head. ^[2] Occasionally, this repetitive swaying motion involves the hindquarters. ^[3]

Stall weaving serves no function or purpose. This stereotypy may develop when a horse is prevented from walking toward a desired goal, such as a feed or other horses. ^[4]

Horses may begin weaving as a result of stress, frustration, their environment, or an inability to express natural equine behaviours. Over time, weaving can cause hoof and joint problems or lead to weight loss if it interferes with eating behaviour.

It is important to understand why your horse is weaving to address the behaviour and avoid long-term effects on health and welfare. If your horse repeatedly exhibits bouts of weaving, discuss potential treatment options with your veterinarian or equine behaviourist.

Stereotypies in Horses

Stereotypies are repetitive patterns of behaviour that seem to have no goal or function. ^[5] An estimated 19.5 – 32.5% of domesticated horses develop stereotypies. ^[2]

Stereotypies can be broken down into oral or locomotive behaviours. Oral stereotypies are more common than locomotor stereotypies and include cribbing, wind-sucking, wood chewing, licking dirt, tongue flicking and teeth grinding.

Locomotor stereotypies include weaving, stall circling or box walking, fence pacing, head shaking, stall kicking and more.

These behaviours are thought to be automated responses or coping mechanisms in response to stress or inadequate management conditions. ^[5] A horse may develop a stereotypy if they are prevented from expressing species-appropriate behaviour.

These behaviours were previously referred to as stall or stable vices. However, this term is now considered inaccurate because it suggests the behaviour represents a moral problem with the horse.

Equine welfare continues to be an important area of research to reduce the prevalence of stereotypies and optimize the well-being of horses kept under human management.

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What Causes Weaving in Horses?

Weaving is an equine behaviour in which the horse remains stationary but repeatedly shifts its weight between forelimbs while laterally swaying its head.

The horse may perform this movement 30 to 90 times per minute, lasting for a few minutes up to several hours per day. ^[6]

Several different factors can contribute to stall weaving in horses. Some identified risk factors include:

• Stress and frustration
• Lack of exercise or turnout
• Social isolation and housing
• Lack of forage in the diet
• Anticipation of reward
• Genetics
• Nervous, reactive personality

Stress and Frustration

Horses can experience stress or frustration in response to many different physical or psychological stressors, including injury, illness, heavy exercise, or sub-optimal environmental conditions.

Horses experiencing high levels of stress may begin to show signs of depression. Your horse may become lethargic or withdrawn, expressing little interest in their environment. ^[7]

To cope with frustrating environments and states of stress, horses may develop stereotypies such as weaving to try and satisfy a specific drive.

Lack of Exercise or Turnout

Horses that do not get enough exercise or turnout are more likely to demonstrate repetitive locomotive behaviours. Confinement for more than 4 hours per day is also associated with higher rates of repetitive behaviour. ^[8]

Exercise deprivation can lead to compensatory locomotor activity, such as intense bouts of cantering, galloping and bucking during turnout, and stereotypic behaviour when stalled. ^[9]

Turnout and exercise provide horses with freedom to express normal equine behaviour, including grazing, running, and free-choice movement. Time outside the stall also helps to prevent boredom.

In one study, horses used for riding lessons had lower levels of the stress hormone cortisol in their saliva compared to horses resting without exercise. This suggests that moderate exercise can reduce stress levels in horses. ^[10]

Small Paddock Size

Horses kept in small paddocks (less than 1.5 hectares or 3.7 acres) are more likely to display repetitive locomotor behaviours. ^[8]

Paddocks of this size may restrict the ability to canter, potentially inhibiting the horse’s expression of free-choice movement. ^[8]

Social Isolation and Housing

Horses are social animals that form herd hierarchies in natural settings. However, domestic management often means that horses are housed in individual stalls for long periods of time.

Individual stalls restrict the horse’s ability to move around freely and limit contact between horses. This isolation and lack of stimulation can lead to frustration.

Increasingly, horses are housed in group settings with freedom of movement and the ability to interact with other horses. This is especially prevalent in some European countries. ^[11]

Research shows that direct contact with other horses lowers stress levels and reduces the prevalence of weaving. ^[12] Social contact with humans or other species can also reduce the expression of stereotypic behaviour. ^[13]

Interestingly, research shows that housing horses in stalls with views of other horses can actually increase stress if the horses cannot achieve close contact. ^[14] Horses kept in box stalls lined up face-to-face with other horses expressed more weaving compared to horses in box stalls lined up side-to-side. ^[13]

However, the risk of behavioural disorders is also increased when visual contact with equine companions is cut off entirely. ^[2]

Lack of Forage in the Diet

Feeding less hay is correlated with higher time spent weaving in horses. ^[13] Diets providing less than 6.8 kg (15 lb) of forage per day are associated with higher rates of weaving, wood-chewing and other abnormal behaviour. ^[8]

The majority of your horse’s diet should be composed of forage. Horses have evolved to graze continuously throughout the day, consuming a diet of high-fibre forages. ^[15]

In comparison, domesticated horses are often fed a few large meals per day consisting of grain-based concentrates or commercial feeds.

When concentrates are added to the diet, less forage is usually offered to the horse. This leads to plenty of idle time between meals during which the horse has no access to forage.

Research shows that altering the natural time budget of the horse can increase active locomotion patterns and lead to the expression of stereotypic behaviours. ^[7]

Restricting access to forage between meals can lead to boredom, stress and frustration in stalled horses. This can increase weaving in anticipation of the next feeding time.

Ideally, horses should have constant access to appropriately selected forage in their stall. Using a slow-feeder hay net can extend foraging time for your horse to prevent idle periods without hay.

Anticipation of Feeding or Turnout

Horses learn new routines quickly and begin to anticipate regularly scheduled feeding or turnout times throughout the day.

Research shows that the frequency and intensity of weaving increase when the horse anticipates being fed. Weaving also increases in horses anticipating palatable concentrate meals and when meals are fed more frequently. ^[2]

Stereotypy expression is also increased when there is greater activity and stimulation in the horse’s environment, such as in the hour before turnout. ^[16]

Pain or Injury

Horses experiencing pain may temporarily perform weaving behaviour. ^[6]

Pain may be associated with a recent injury, dental problem, joint issue, colic, laminitis, hoof disorder or other cause. If you think your horse is weaving because of pain, consult with your veterinarian to obtain a diagnosis.

Breeds and Genetics

Certain breeds, including Thoroughbreds and Warmbloods, are more prone to developing stereotypies than other breeds, such as Standardbreds, Arabs and ponies. ^[2] The tendency to weave may also be inherited, suggesting a genetic link. ^[6]

Thoroughbreds are thought to be high-strung and to have a higher risk of weaving behaviour. ^[13] However, Thoroughbreds are also commonly used in performance sports, and the higher rates of weaving may reflect typical management practices in those disciplines as opposed to breed differences.

Copying Behaviour

It was previously thought that horses mimic stereotypic behaviours expressed by other horses in their environment. However, the theory that stereotypies are learned behaviours from copying other horses has been disproven. ^[16]

Some boarding facilities continue to separate stereotypic horses from other horses to prevent them from mimicking each other. Unfortunately, social isolation causes stress and can reinforce these behaviours. ^[17]

Weaning Practices

Weaning practices can significantly affect the risk of stereotypic behaviour in horses. It is recommended to wean horses gradually and in group settings.

Paddock- or group-weaning strategies are associated with a lower risk of abnormal behaviours compared to individual stall weaning. ^[8]

Compensating for Another Stereotypy

Horses may express weaving behaviour if they are prevented from performing another locomotor stereotypy.

Horses that were tied to prevent stereotypic circling or pacing behaviour have been observed to weave for up to three hours per day. ^[6]

Additional Associated Factors

An abstract at the 2005 American Association of Equine Practitioners Convention noted the following findings in horses displaying weaving: ^[8]

• The median age at which horses begin to display weaving is 60 weeks (approximately one year and two months old)
• The horse has a highly predictable management routine
• The horse does not show signs of lameness
• The horse’s bedding is not straw

Problems Associated with Weaving in Horses

Is weaving bad for horses? Short-term bouts of swaying side-to-side are unlikely to harm your horse, but continued stereotypic behaviours could negatively affect the horse’s well-being.

Performing locomotor stereotypies over long periods could potentially contribute to: ^[2][3]

• Fatigue and poor performance
• Weight loss
• Loss of appetite
• Muscle damage
• Hoof wear
• Joint stress
• Ligament strains
• Tendon injuries

The AAEP notes there is a lack of research into the consequences of weaving for horses and recommends further investigations of the subject. ^[8]

How to Reduce Weaving in Horses

To help a horse that is weaving, it is crucial to identify and eliminate the underlying cause of the behaviour.

Examine your horse’s environment, routine, and feeding program to identify potential risk factors that could be contributing to stereotypic behaviours.

Consider adopting some of the following management practices to support your horse’s welfare and reduce stress.

It is not recommended to stop your horse from weaving by physically preventing the motion. The use of anti-weaving devices can worsen your horse’s stress and lead to the development of other stereotypies.

Limit Stall Confinement and Increase Turnout

Keeping horses in stalls for extended periods of time may be a common management practice, but it can also contribute to stereotypic behaviours such as weaving.

The simplest way to prevent weaving is to increase turnout on pasture and limit stall confinement to less than 4 hours per day. ^[8][15]

Housing horses in an environment that closely mimics their natural habitat can improve mental and physical well-being.

Daily free movement outside of the stall allows horses to perform natural behaviours that they cannot exhibit while confined, such as grazing and walking.

Increasing Exercise

Increasing exercise frequency and duration can also reduce instances of weaving, and a lack of exercise is thought to contribute to this stereotypy. ^[15]

Wild horses typically take 10,000 strides daily while expressing normal feeding behaviours. ^[2] Exercise allows the horse to express movement and may eliminate the underlying motivation to perform locomotor stereotypies. ^[8]

Free-Choice Access to Forage

Horses provided with ad-libitum or free-choice access to roughage are less likely to exhibit stereotypic behaviour.

Avoid using energy-dense concentrates and feed your horse a forage-based diet. Provide at least 6.8 kg (15 lb) of forage per day for a 500 kg (1100 lb) horse. ^[8]

In one case study, a weaving horse was put on a forage-only diet with flakes of hay distributed at different foraging stations around the stall.

This transformed the horse’s locomotor stereotypic behaviour into a slower, relaxed grazing-like motion that mimicked the natural foraging behaviour of the horse. ^[6]

If your horse tends to weave when anticipating a meal, try to remove any cues that indicate feeding time. ^[15] This may only be a short-term solution as horses can learn to associate other cues with meal time.

Healthy Herd Dynamic

Increased positive social contact can reduce the expression of weaving and other locomotor stereotypies. ^[8] Allow your horse to form healthy social relationships with other horses to support their mental well-being.

Horses kept within preferred social groups display more allogrooming (social grooming between two horses) and play. ^[18] This can reduce stress, as measured by blood cortisol levels in horses. ^[19]

Monitor your horse’s socialization to ensure they are in a compatible friend group. Horses with a low social standing in their herd can have higher stress levels. ^[20]

Frequent regrouping of horses for turnout in a domestic environment can lead to unstable relationships and increase stress. Research shows that young horses are especially affected by the inability to form stable social groups. ^[21]

Housing Design

Periods of weaving are reduced when stalled horses can see, touch and interact with their neighbours. ^[12] Use bars between box stalls to facilitate contact between horses.

Some facilities are opting for group housing systems to promote equine welfare and provide mental stimulation to domesticated horses. ^[22]

The HIT Active Stable® concept is a modern design that promotes social interaction between horses, provides a track system for exercise and gives horses constant access to water, forage, and feed.

Implementing a new housing system is difficult and expensive, and individual stalls remain the norm in the equine industry. However, it is worth considering other options to individual stalling for your horse.

Hang Mirrors in your Horse’s Stall

Hanging mirrors in the horse’s environment can replicate social contact and reduce anxiety when equine companions are unavailable. ^[3] Printed posters of horses also appear to be effective for reducing weaving. ^[2]

It is recommended to hang a mirror at the front of the stall so the horse sees its own reflection when it would normally engage in weaving. ^[8]

Mirrors are a relatively low-cost intervention, but results are highly variable. ^[3] In some horses, the effects wear off after a short time while other horses do not see improvements in weaving with mirrors.

However, there are case reports of chronic weavers that stopped the behaviour within 24 hours of a mirror being installed in their environment. ^[8]

Provide Enrichment

Providing your horse with stall toys or enrichment activities can help to prevent boredom and reduce stress.

Some stall toys are designed to reduce stereotypic behaviours in horses by disrupting established habits. ^[4] Feed toys can reduce anticipatory behaviours by extending feeding time and lowering feeding motivation before the next meal.

Introducing a novel object to the stall may temporarily interrupt weaving by distracting your horse. Any new visual stimulation or change in environment could temporarily redirect your horse’s focus away from the expression of weaving.

Use Straw Bedding

The incidence of weaving appears to be higher in horses with bedding material other than straw, although the reasons for this association are not well-understood

Using straw bedding is recommended to reduce weaving in horses. ^[8]

Medications

If weaving is causing a significant welfare concern for your horse, your veterinarian may recommend treatment with pharmaceutical drugs. However, the AAEP generally recommends against the use of drugs for weavers. ^[8]

Preliminary findings suggest that tricyclic antidepressant medications may benefit horses exhibiting locomotor stereotypies. One case report noted positive results in seven horses expressing weaving, circling and fence-walking behaviours. ^[6]

Medication may not be appropriate for your horse and is only ever used as a last resort when other interventions have failed. Consult with your veterinarian to learn about risks and other treatment options.

Physical Barriers

Weaving can be prevented by installing physical barriers such as weaving bars or grills, restricting harnesses or head collars, but this practice is not recommended.

Physically preventing horses from expressing stereotypies does not treat the underlying cause of the behaviour and can lead to distress in the horse. ^[23]

Stereotypies are a coping mechanism for horses experiencing stress. Removing the coping mechanism by preventing your horse from weaving may only worsen your horse’s frustration.

Conclusion

Weaving is an example of a stereotypic behaviour expressed by horses in response to stress or frustration. It may be caused by a lack of freedom, insufficient forage in the diet, boredom, pain, social isolation, or environmental factors related to housing and management.

The best way to reduce your horse’s weaving is to address the underlying factors triggering the behaviour. Follow some of the welfare recommendations in this article to reduce your horse’s stress and support their overall well-being.

Consult with your veterinarian about any health concerns and work with a equine nutritionist to formulate a balanced feeding program for your horse that provides adequate forage.

Submit your horse’s information online for a free diet evaluation by our qualified equine nutritionists. Our nutritionists can also help you review factors in your horse’s routine and management that could contribute to stereotypies such as weaving.