Abnormal or unusual eating behavior is not uncommon in horses and might be of concern to a horse owner.

Foals frequently nibble at manure, which is one way the microbial population of the gut is established. It might not look attractive, but is normal investigative behavior. Other unusual eating behavior includes chewing on fences or stall walls, eating bark off trees, chewing on stablemates’ tails, and eating dirt. In some species, the term “pica” is used to indicate consuming unusual food.

Except for salt, and perhaps phosphorus, there has been limited information to document that horses have nutritional wisdom for selecting nutrients. Horses can select and consume plants that taste better than other plants