How big a chicken coop do you need?
About 4 sq ft of floor inside and 10 sq ft of run for each standard-size hen. Add one nest box for every 4 hens and 8 to 10 in of roost bar per bird.
The four numbers
- Inside floor: about 4 sq ft per hen. Less, and birds that spend winter days indoors start pecking each other. Bantams manage on about half; big breeds like Brahmas want more.
- Run: about 10 sq ft per hen. The space under a raised coop counts toward it.
- Nest boxes: one per 4 hens. They share. Boxes about 12 in square, lower than the roosts so nobody sleeps in them.
- Roost: 8 to 10 in of bar per hen. A 2x4 laid flat lets them cover their feet in cold weather.
Coop size by flock
| Hens | Coop | Inside floor | Run | Nest boxes | Roost | Materials |
|---|---|---|---|---|---|---|
| 3 hens | Raised | 12 sq ft | 32 sq ft | 1 | 41 in | $869 |
| 4 hens | Raised | 16 sq ft | 40 sq ft | 1 | 41 in | $984 |
| 5 hens | Raised | 20 sq ft | 52 sq ft | 2 | 82 in | $1,036 |
| 6 hens | Raised | 24 sq ft | 60 sq ft | 2 | 82 in | $1,124 |
| 8 hens | Raised | 32 sq ft | 80 sq ft | 2 | 82 in | $1,323 |
| 10 hens | Walk-in | 48 sq ft | 104 sq ft | 3 | 130 in | $2,702 |
| 12 hens | Walk-in | 48 sq ft | 120 sq ft | 3 | 130 in | $2,784 |
| 15 hens | Walk-in | 64 sq ft | 152 sq ft | 4 | 178 in | $3,112 |
| 20 hens | Walk-in | 80 sq ft | 200 sq ft | 5 | 267 in | $3,573 |
| 25 hens | Walk-in | 100 sq ft | 250 sq ft | 7 | 339 in | $4,310 |
| 30 hens | Walk-in | 120 sq ft | 300 sq ft | 8 | 339 in | $4,806 |
Materials are typical big-box prices for the whole build: lumber, plywood, roofing, hardware cloth, hinges and latches.
Raised coop or walk-in?
Up to about 8 hens, a raised coop on legs works well: the run continues underneath, and you collect eggs and clean out through doors from outside. Past that, a walk-in coop you can stand up in is easier to keep clean, and the run becomes its own walk-in pen.
Plan for one more hen
Most keepers add birds in the second year. If you are between two rows, build the bigger one: the extra lumber costs far less than rebuilding.
What keeps them safe
Use 1/2 in hardware cloth, not chicken wire, on every side of the run and on top, and bury a 12 in apron around the edge so nothing digs under. Raccoons open simple hooks; two-step latches stop them. Leave about 1 sq ft of screened vent for every 10 sq ft of floor, high under the roof.
Every coop plan sizes the house, run, nests and roosts for your flock and prices the lumber.
Size a coop for your flock