Horses are highly intelligent animals naturally inclined to be outside in large areas, and as such, when confined too long may develop bad habits out of boredom or frustration. A common habit that horses develop to ease their boredom and frustration is chewing on their wood stalls or other wood in their enclosures.
Not only does chewing damage the wood, but it can also create problems for the horse such as causing undue wear on the incisors and the chance of splinters being lodged in the mouth or swallowed.
There are some medical issues, such as vitamin deficiencies, that may compel a horse to chew wood. But most of the time a horse that's chewing on wood is a bored horse.
Why Do Horses Chew Wood?
There are a few reasons why horses chew wood. It's worth noting that wood chewing is not typically observed among wild horses, so this is a behavior that typically results from keeping a horse in an unnatural environment.
Horses kept in stalls or paddocks, secluded from other horses, or fed mostly concentrates without enough fodder to keep them chewing over a long period of time may become bored and chew fences for something to do.
Occasionally, vitamin deficiencies may cause a horse to develop pica—a taste for eating nonedible substances in an effort to alleviate the deficiency. This is not as common, but pica may indicate a serious underlying nutritional or hormonal problem.
Some horses may have learned to gnaw wood from stable or pasture mates. Like mischievous kids, they try what the other kids are trying, even if they would never have thought of it on their own—and the habit sticks. This is a bit of a trickier situation when it comes time to train the horse out of the wood-chewing behavior, because you may need to involve more than one horse in your efforts.
Horses that crib can be hard on wood (and other surfaces) too. However, this isn't truly wood chewing.
Cribbing, formally referred to as aerophagia, is an obsessive-compulsive disorder (again, found only in domesticated horses), where the horse sinks its incisors into an upright object like a fence post, then pulls against the object while inhaling and arching its neck. The horse isn't really chewing on the wood since it doesn't break off or swallow any pieces; it's more like leaning on the surface in order to forceably gulp air.
How to Stop Wood Chewing
Once your veterinarian has ruled out any medical or nutritional issues, you can start addressing the behavior that's causing your horse to chew wood.
Keep Your Horse Outdoors
Horses that are kept indoors are more likely to develop habits to try to alleviate their boredom and frustration. Outdoors, some horses may get bored because there may be little to do once they eat all their hay. Horses in the wild spend the majority of their time grazing.
Allowing horses to live as naturally with other horses as possible, outdoors with plenty of grass or hay to nibble on, can help prevent wood chewing. But there are times when outdoor turnout isn't possible, such as when a horse has an injury requiring stall rest, if there isn't space or resources for all-day turnout, or conditions such as icy pastures make it dangerous for horses to be out.
Treat or Protect Wood Surfaces
Applying sprays, pastes, or washes that have a bitter taste painted onto the wood surfaces may be an option. The downside of such products is that they get washed off in the rain, and some horses don't seem to notice the taste. Additionally, make sure what you are applying to the wood is non-toxic.
You can nail metal caps over fence rails and posts, protectively wrap trees, and use plastic mesh as well. A string of electric fencing along the top rail of a fence usually keeps determined chewers back, and you can try setting up little pens around trees to prevent your horse from getting close enough to chew.
Socialize Your Horse
Along with more outdoor activity, socializing your horse with other horses may help alleviate some of its boredom. But don't pair up two horses that both chew on wood, and take care that the wood chewer doesn't end up being a bad influence on its nonchewing stablemate.
Give Your Horse a Toy
You may also want to provide your horse with a toy to play with to direct its attention away from wood surfaces, such as a large rubber ball.
Check Your Horse's Diet
Discuss this with your veterinarian first, but there's some evidence that when the amount of grain in a horse's diet is reduced, the horse is less likely to chew wood or engage in cribbing. Also be sure to offer your horse as much roughage as possible, to satiate your horse's natural grazing instinct.
Finding the right solution to wood chewing can save you money as well as ensure your horse's good health.