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How does a chicken flock’s social hierarchy affect access to food and nesting sites?

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A peacock stands with its vibrant green and blue tail feathers fully fanned out in display, showing eye-like patterns across the plumage. — Galliform Blue, or Indian, peacock (*Pavo cristatus*) displaying its resplendent feathers.

In a chicken flock, the social hierarchy—known as the pecking order—is a fundamental system that dictates access to essential resources, including food and nesting sites.12

This hierarchy is segregated by sex and functions as a social ranking where higher-ranking individuals maintain their status and priority access to resources by pecking, or sometimes using their wings and claws, against those of lower rank. Because individuals of higher social rank can strike out at subordinates without fear of retaliation, they effectively secure their preferred access to food and nesting areas.21

This structure is established early, often by the 10th week of life in female chicks, and serves to organize the flock's daily interactions and resource distribution. When new birds are introduced to an existing flock, challenges to this hierarchy frequently occur, which can lead to aggressive altercations as the birds re-establish their relative positions.2