A coop is a small enclosed area or structure where chickens are kept. If you feel cooped up, you feel like you’re stuck in a small space, like a giant chicken in a tiny cage.
A coop is where chickens get shelter from bad weather and predators. Without a hyphen, the word co-op, which is short for co-operative organization, turns into coop. That can be confusing to chickens because they don’t know if they will have meetings or a safe place to lay eggs. Coop comes from the Old English word cype, "basket" or "cask," with the Latin root cupa, "cask" or "tub."