Why can introducing a new chicken into a flock lead to fighting?

Introducing a new chicken into an existing flock often triggers fighting because the birds must re-establish their social hierarchy, commonly known as the pecking order.

In a stable flock, each bird occupies a specific rank that determines its access to essential resources such as food, nesting sites, and mates. When a new bird is introduced, it disrupts this established order, prompting existing members to challenge the newcomer or each other to defend or improve their status. These altercations can involve pecking, scratching with claws, and pummeling with wings.1

While these social dynamics are natural, they can be dangerous; fights for dominance—particularly among males—carry a significant risk of injury or death. Because of this, effective management in poultry farming often focuses on creating controlled environments that minimize stress and conflict among the birds.12