UNUSUAL eating behaviours such as licking soil, chewing wood or eating faeces are often assumed by owners that their horses are lacking something within their diet. These feeding behaviours are known as forms of pica, a desire to eat unusual substances.

However, horses only show a true appetite for three nutrients – energy, salt and water – and often these unusual behaviours can be due to boredom or curiosity. Studies conducted in the 1970s concluded with this premise.