Is it ensure, insure, or assure?
A hierarchy within a social group or community, in which those members at the top assume positions of leadership, authority, and power. The expression originated from a description of social behavior among chickens, which attack each other by pecking to establish dominance.
a form of animal social structure in which a linear or nearly linear ranking exists, with each animal dominant over those below it and submissive to those above it in the hierarchy. Dominance hierarchies are best known in social mammals, such as baboons and wolves, and in birds, notably chickens (in which the term peck order or peck right is often applied)