A halter to be worn by pigs, particularly weaning sows, to restrict or prevent fighting and aggressive biting while allowing the animal to move freely and eat and drink includes a noose which can be selectively adjusted in girth when placed round the muzzle of the pig to limit opening of its jaws. Preferably the noose is formed with a slip ring. The halter further includes a collar for the pig's neck to which the noose is secured.
