Chicken Coop Size Calculator — Coop Area, Run & Boxes
A flock's coop floor area, outdoor run area, and nesting boxes come from its size — enter your flock count to get all three, based on standard rates.
How it works
Backyard flocks need two spaces: an enclosed coop for roosting and laying, and a run for daytime activity. Each is sized per bird. Extension poultry guidance puts a standard laying hen at about 3 to 4 square feet of coop floor and 8 to 10 square feet of run, so the calculator multiplies your bird count by the rate you choose for each and adds them for a total footprint.
Nesting boxes follow a separate rule of thumb: about one box for every 3 to 4 hens. Hens share and often queue for a favorite box, so more boxes rarely hurt while too few lead to squabbling and floor-laid eggs. The tool rounds the box count up, because you cannot install a fraction of a box.
These are minimums for healthy, low-stress birds. Crowding drives pecking, disease, and stress, so when in doubt, build bigger — especially for the run, where birds spend daylight hours. Bantams need less and large or active breeds appreciate more, which is why the per-bird rate is adjustable.
coop floor = 6 × 3 = 18 sq ft (about 1.7 m²)
run = 6 × 10 = 60 sq ft (about 5.6 m²) · nesting boxes = ceil(6 ÷ 4) = 2