Horses are magnificent creatures known for their grace, intelligence, and athleticism. As herd animals that have evolved to roam and graze for up to 18 hours a day, they possess specific behavioral needs that must be met to ensure their mental and physical well-being. When these needs aren’t properly addressed, horses can develop abnormal behaviors known as stereotypies—repetitive patterns with no apparent function or purpose.

While these behaviors might initially seem harmless, they can signal serious underlying issues, eventually leading to health problems and property damage. As a responsible horse owner or caretaker, recognizing and addressing these abnormal behaviors is crucial for your equine companion’s welfare.

Understanding Stereotypies: The Silent Cry for Help

Stereotypies are essentially coping mechanisms that horses develop in response to stress, frustration, boredom, or unmet physical and psychological needs. Dr. Katherine Houpt, a veterinary behaviorist from Cornell University, describes them as “behavioral scars” that indicate a horse has experienced significant stress, particularly during critical developmental periods.

Unlike normal behaviors that serve a purpose (such as grooming for hygiene or pawing to access food), stereotypies are repetitive actions that serve no functional goal. They’re often described as “vacuum behaviors”—actions performed without the normal environmental triggers or outcomes.

Research suggests that stereotypies may activate the brain’s endorphin system, creating a self-rewarding cycle that makes these behaviors difficult to eliminate once established. This is why early intervention is vital when signs first appear.

Let’s explore seven of the most concerning abnormal behaviors in horses and what you can do to address them.

1. Cribbing (Crib-biting): More Than Just a Bad Habit

What it looks like: A horse grabs onto a fixed object—typically a fence rail, stall door, or water bucket—with its incisor teeth, arches its neck, and pulls backward while sucking in air. This action is usually accompanied by a distinctive grunting or gulping sound.

Why it matters: Cribbing is perhaps the most concerning stereotypy due to its potential health implications. When horses crib, they swallow air, which can lead to:

• Increased risk of colic, particularly gas colic
• Dental problems including excessive wear on incisor teeth
• Weight loss and poor condition due to reduced feeding time
• Gastric ulcers, which may both result from and contribute to cribbing
• Damage to wooden structures around the stable

The science behind it: Research from the University of Bristol found that cribbing horses have higher levels of gastric ulceration than non-cribbers. The behavior may actually provide some relief from gastric discomfort, creating a vicious cycle.

Addressing the behavior:

• Provide consistent access to high-quality forage
• Ensure regular turnout with companions
• Consider a specialized diet to address gastric issues
• Consult a veterinarian about medications for ulcer treatment
• Avoid punitive anti-cribbing devices that address only the symptom and not the cause

While cribbing collars and similar deterrents may temporarily prevent the behavior, they don’t address the underlying issues and may increase stress levels.

2. Weaving: The Rhythmic Distress Signal

What it looks like: A horse stands in place, repeatedly shifting its weight from one foreleg to the other while swinging its head and neck from side to side in a rhythmic, pendulum-like motion.

Why it matters: Weaving puts abnormal stress on a horse’s front legs, particularly the joints, potentially leading to:

• Premature joint wear and lameness
• Weight loss due to constant energy expenditure
• Fatigue affecting performance
• Hoof issues from uneven weight distribution

The science behind it: Researchers at Nottingham Trent University found that weaving increases significantly before feeding times and in horses with limited visual horizons. The behavior likely stems from frustrated attempts to move forward or seek social contact.

Addressing the behavior:

• Provide maximum turnout with compatible herd mates
• If stall confinement is necessary, use stalls with partial walls or grills that allow horses to see neighbors
• Establish consistent routines, especially around feeding times
• Consider paddock arrangements that allow visual contact with other horses
• Create environmental enrichment through multiple forage options placed at different locations

One stable found success by installing mirrors in stalls, which appeared to satisfy some horses’ need for visual companionship, though results vary by individual.

3. Wood Chewing: Beyond Simple Destruction

What it looks like: The horse repeatedly bites, scrapes, and ingests wooden structures such as fencing, stall walls, or posts. Unlike cribbing, there’s no arching of the neck or air-sucking involved.

Why it matters: Beyond costly property damage, wood chewing can cause:

• Dental issues from irregular wear patterns
• Ingestion of harmful preservatives in treated wood
• Splinters in the mouth or digestive tract
• Increased risk of impaction colic from wood consumption
• Potential toxicity from consuming certain wood types

The science behind it: A study in the Journal of Veterinary Behavior found that wood chewing increases dramatically when horses are fed restricted forage diets. The behavior appears linked to a biological need for continuous fiber intake and the natural chewing motion that would occur during grazing.

Addressing the behavior:

• Ensure horses receive at least 1.5% of their body weight in forage daily (approximately 15-18 pounds for a 1,000-pound horse)
• Split hay portions to extend feeding time throughout the day
• Use slow-feed hay nets to prolong eating time
• Add safe browsing options like non-toxic branches (willow, apple, or poplar)
• Consider adding a higher fiber component to the diet

Some owners report success with commercial bitter-tasting sprays for wood surfaces, though these must be frequently reapplied and don’t address the underlying causes.

4. Stall Kicking: Aggression or Anticipation?

What it looks like: The horse repeatedly kicks or strikes barn walls or doors with its front or hind feet, often creating a distinctive rhythmic banging.

Why it matters: This destructive behavior can lead to:

• Hoof and leg injuries including bruising, swelling, or even fractures
• Stall damage requiring expensive repairs
• Disruption to other horses in the barn
• Development of chronic inflammation in joints
• Potential unsafe conditions from damaged structures

The science behind it: Research indicates stall kicking often peaks around feeding times or other anticipated events. A study from the Swedish University of Agricultural Sciences linked kicking to frustration resulting from restricted movement and the inability to engage in natural herd activities.

Addressing the behavior:

• Evaluate and adjust feeding schedules to reduce anticipatory behavior
• Use random feeding times to reduce predictability-induced excitement
• Provide additional turnout or exercise opportunities
• Install rubber mats or wall padding to reduce injury risk and noise
• Consider moving a chronic kicker to an end stall to reduce stimulation

One innovative approach involves using automated feeding systems that dispense small amounts throughout the day, reducing the anticipation that triggers kicking episodes.

5. Box Walking: The Endless Journey to Nowhere

What it looks like: The horse walks continuously around the perimeter of its stall in a repetitive circular pattern, often creating a well-worn track along the edges.

Why it matters: This seemingly simple behavior can result in:

• Significant weight loss and condition deterioration
• Excessive energy expenditure leads to fatigue
• Hoof wear problems from constant turning
• Reduced rest periods affecting overall health
• Loss of performance ability due to constant activity

The science behind it: Box walking mimics natural migration behavior but in a severely restricted space. Research from the University of Lincoln suggests it’s most common in horses that previously enjoyed extensive turnout or those experiencing significant environmental changes.

Addressing the behavior:

• Maximize turnout opportunities
• If stabling is necessary, provide the largest possible space
• Maintain consistent routines and caretakers
• Introduce changes gradually when possible
• Consider companion animals if appropriate
• Use multiple feeding stations to encourage movement in productive ways

A case study from a rehabilitation center found that transitioning box walkers to paddock living with compatible companions resolved the behavior in 80% of cases within three weeks.

6. Tail and Mane Chewing: Self-Mutilation or Boredom?

What it looks like: Horses chew on their own tails or manes, or those of herd mates, resulting in ragged, shortened, or broken hair. In severe cases, the tail may be chewed down to a short stub.

Why it matters: While seemingly less harmful than other stereotypies, this behavior indicates significant welfare issues and can cause:

• Skin irritation or infection at chewed sites
• Loss of natural fly protection
• Damage to other horses if they’re the targets
• Indication of serious nutritional deficiencies in some cases
• Possible pain or discomfort from underlying conditions

The science behind it: While boredom is a factor, research has linked some cases to mineral deficiencies, particularly phosphorus, salt, or protein. A study in Applied Animal Behaviour Science found correlations between mane/tail chewing and restricted forage access.

Addressing the behavior:

• Evaluate diet for potential mineral imbalances
• Ensure adequate salt intake through free-choice salt blocks
• Increase enrichment opportunities with toys and varied forage
• Provide regular grooming to address possible skin irritation
• Consider separation from other horses if they’re the targets

Some owners report success with bittering agents applied to the tail, but these require frequent application and monitoring to ensure they don’t cause skin irritation.

7. Fence Walking: The Boundary Patrol

What it looks like: The horse walks, trots, or paces continuously along a fence line, often creating a deeply worn path parallel to the boundary.

Why it matters: This less-discussed but concerning behavior can result in:

• Significant energy expenditure and weight loss
• Development of uneven muscle tone
• Reduced grazing time affects nutrition
• Potential for injury from repetitive motion
• Erosion issues along fence lines

The science behind it: Fence walking often develops when horses are separated from companions or can see activities they cannot access. A study from Hartpury College found it’s particularly common following changes in group composition and during breeding season in stallions and mares.

Addressing the behavior:

• Evaluate and adjust herd compositions to reduce social stress
• Provide compatible companions
• Consider paddock layouts that reduce visual triggers
• Create enrichment zones away from fence lines
• Use double fencing between potentially incompatible groups

One innovative solution employed by a therapeutic riding center involved creating curved fence lines rather than straight boundaries, which significantly reduced fence walking behavior.

Prevention: The Best Treatment

While addressing existing stereotypes is important, preventing their development is far more effective. Horses evolved as social herd animals that move and graze continuously; management practices that honor these natural needs will significantly reduce abnormal behavior risk.

Key preventive strategies include:

• Maximum Turnout: Provide as much free movement time as possible, ideally with compatible companions.
• Forage-Based Nutrition: Ensure horses can engage in natural grazing behavior for at least 12-18 hours daily.
• Consistent Routines: Establish predictable patterns for feeding, turnout, and handling.
• Social Opportunities: Allow for appropriate interaction with other horses, even if just visual contact.
• Environmental Enrichment: Provide variety through different forage types, feeding locations, and safe toys.
• Gradual Transitions: Introduce any changes to the environment, diet, or routine slowly.

When to Seek Professional Help

If you notice your horse developing any of these behaviors, consult with an equine veterinarian promptly. They can:

• Rule out medical causes that might contribute to abnormal behaviors
• Provide guidance on appropriate management changes
• Recommend specialized professionals like equine behaviorists if needed
• Discuss whether pharmaceutical interventions might be appropriate in severe cases

Remember that stereotypies rarely disappear completely once established, but their frequency and intensity can be significantly reduced with appropriate management. The goal should be improving welfare rather than simply eliminating the visible behavior.

By recognizing these warning signs early and taking appropriate action, you can help ensure your horse leads a physically and psychologically healthy life. Your attentiveness to these behavioral indicators demonstrates the deep commitment required for responsible horse ownership.

A balanced diet, proper exercise, and regular socialization will make a huge difference. Make sure that all of your horse’s needs are met to ensure proper mental and physical health.