Blue Riley, hi. Usually when a horse chews on odd things, bites or eats things it is a sign on their needing loose salt. Children do this too when they are salt deficient. I noticed a number of people who responded also had similar behavioral issues with their horses as well. Not always, but in many cases it is a sign of a salt deficiency. The only salt good for a horse is loose salt, for horses. In the winter months they need at least 1 ounce of salt a day, and in the summer months when warmer/hotter or when excersised, ridden regularly or – when the horse is in events they require at least 4 ounces of salt a day. So winter 1 ounce of salt a day mixed into their diet, or in a feeder in their stall, and in the winter or when being exercised regularly or ridden regularly they require at least 4 ounces of salt. This is very important they have this or they will chew, bite, eat odd things not good for them. I am not sure if your horse is already getting daily loose salt, but its important. Just wanted to offer this advise to you, it could be bad behavior but you might want to try loose salt either mixed in the food or else in a covered stall feeder. Good luck!