The social organization of domesticated pigs, sus scrofa, living
under farm conditions is, as in wild pigs, based upon a dominance
hierarchy (McBride et al., 1964). Hierarchy develops as a part of
pig’s social life and is a form of group organization. Establishment
of social hierarchy results in division of a group of pigs to sub-
groups of dominants, subdominants, submissive, subordinate and
marginal. Two types of dominance hierarchy can develop in a