What is a pecking order in a flock of chickens?

In a flock of chickens, a pecking order is a social hierarchy that dictates access to essential resources such as food, nesting sites, and mates. Within this structure, each bird occupies a specific rank: individuals of higher status may peck those of lower rank without fear of retaliation, while lower-ranking birds must submit to those above them.123

This social organization is typically segregated by sex. In groups of female chicks, the hierarchy is generally established by the 10th week of life, whereas in groups of males, competition for dominance can persist into adulthood. While pecking is the primary manifestation of this hierarchy, altercations may also involve scratching with claws or pummeling with wings. When a new bird is introduced to an established flock, challenges to the existing order often occur, which can lead to aggressive fights, particularly among males.1