Stereotypic behaviours in horses including crib-biting, weaving, and box-walking indicate chronic frustration and are both welfare indicators and welfare problems in their own right.
Equine stereotypies are welfare indicators of a systematic problem: horses are athletic, social, wide-ranging animals that in most domestic situations spend the majority of their time in isolated box stalls with limited movement and no opportunity for natural grazing or social behaviour. The boredom, frustration, and gastric discomfort that result can drive the development of stereotypic behaviours that, once established, become self-perpetuating. Physical prevention of stereotypies using anti-weaving grills or cribbing collars prevents the expression of the behaviour without addressing the underlying welfare deficit — and research suggests that prevention worsens overall welfare outcomes. The welfare-positive approach is to identify and address the underlying causes: increase turnout time, social contact with other horses, forage availability, and environmental complexity. Early intervention before behaviours become established is far more effective than managing them after the fact.