The heels can make or break the HPA (Hoof-pastern alignment). The heels grow forward on an angle. The longer the heels get, the further forward the weight-bearing position. Depending on conformation, some horses will either grow tall heels, or get crushed heels. Upright and club hooves are more prone to tall heels and get a broken-forward HPA. Slopey and long-pasterns/sickle hocks/camped under types are more prone to underrun or crushed heels, which creates a broken-backward ... wedding of lace