Chicken Coop Size Calculator

About this calculator

Coop sizing follows per-bird space guidelines from poultry-keeping extension services: roughly 2 to 4 square feet of indoor coop floor per standard-size hen (more for larger breeds, less for bantams), 8 to 10 square feet of outdoor run per bird if they are not fully free-ranging, 8 to 12 inches of roost bar length per hen for overnight perching, and one nesting box for every 3 to 4 hens since they will happily share.

Backyard poultry keepers use this calculation before building or buying a coop, because undersizing any one of these — floor space, run space, roost length or nest boxes — leads directly to stress, feather-pecking and reduced egg-laying, while a coop sized only for today's flock leaves no room if a few more chicks get added next spring.

This calculator takes your flock size and returns the coop floor area, run area, roost bar length and number of nesting boxes your birds need, so you can plan a coop that keeps a healthy, low-stress flock rather than a crowded one.