What Size Coop for 4 Chickens?
4 standard hens need 16 sq ft of coop floor and 40 sq ft of run, plus 2 nest boxes and 3 ft 4 in of roost. Adjusted for breed, climate and setup.
4 standard-size hens with access to a run need 16 square feet of coop floor and 40 square feet of run, plus 2 nest boxes and 3 ft 4 in of roost bar. Confined without a run, the coop figure rises to 40 sq ft. In a cold climate add about 25%, giving 20 sq ft. Heavy breeds need 20 sq ft; bantams 8.
Change the breed, climate or setup and see the numbers move with the coop size calculator.
What size coop for 4 chickens?
For 4 standard-size hens — Plymouth Rocks, Orpingtons, Rhode Island Reds — that spend their days in a run:
| What | How much | Why |
|---|---|---|
| Coop floor | 16 sq ft | 4 sq ft per bird, sleeping and laying space |
| Run | 40 sq ft | 10 sq ft per bird of enclosed outdoor space |
| Nest boxes | 2 | Two minimum, then about one per four hens |
| Roost bar | 3 ft 4 in | 10 inches per bird, splittable across bars |
| Ventilation | 576 sq in | High-mounted, to clear moisture and ammonia |
A 4×4 footprint gives 16 sq ft, which covers it. The run wants 40 sq ft alongside it.
If the setup is different
The coop figure assumes the birds get outside every day. Change that and it moves:
| Setup | Coop floor | Run |
|---|---|---|
| With a run (the usual case) | 16 sq ft | 40 sq ft |
| Confined, no run | 40 sq ft | — |
| Free-ranging most of the day | 12 sq ft | 40 sq ft or open ground |
Confining birds without a run roughly doubles what the coop has to provide, because it stops being a bedroom and becomes the whole living space.
By breed
Body size moves the figure more than most people expect:
| Breed tier | Examples | Coop | Run | Roost |
|---|---|---|---|---|
| Heavy | Brahma, Jersey Giant, Cochin | 20 sq ft | 48 sq ft | 3 ft 4 in |
| Standard | Plymouth Rock, Orpington, Rhode Island Red | 16 sq ft | 40 sq ft | 3 ft 4 in |
| Light | Leghorn, Hamburg, Andalusian | 12 sq ft | 32 sq ft | 3 ft 4 in |
| Bantam | Silkie, Sebright | 8 sq ft | 24 sq ft | 1 ft 4 in |
A mixed flock takes the larger figure. 4 birds that include heavy breeds should be sized as 4 heavy birds — the big ones do not confine themselves to their share.
Cold climates
In a cold climate, add about 25% to the indoor figure: 20 sq ft for 4 standard hens rather than 16.
Not because chickens need more room when cold — they huddle for warmth — but because a cold-climate flock spends far more days shut in, and the moisture from droppings and breathing has to go somewhere. Winter coop trouble is usually a crowding and ventilation problem wearing a temperature costume. The 25% figure is a Flockmath planning convention rather than a published minimum; the direction is supported, the number is ours.
Room to grow
Most people who start with 4 hens end up with more. Flock size creeps: a broody hen hatches a clutch, a neighbour rehomes theirs, or the first spring of reliable eggs makes the case for a few more.
Building at 16 sq ft locks you to 4 birds. Adding a couple of square feet per bird at build time is cheap; extending a finished coop is not. If there is any chance of going to 8, size the floor for 8 now — 32 sq ft — and enjoy the extra space in the meantime. Chickens never object to more room.
Frequently asked questions
How big should a chicken coop be for 4 chickens?
16 square feet of floor for 4 standard-size hens with a run, plus a 40 square foot run. Confined without a run, 40 square feet.
How many nest boxes for 4 chickens?
- The rule is two minimum, then roughly one per four hens. Extra boxes past that are mostly wasted — hens cluster on one or two favourites regardless.
How much roost space for 4 chickens?
3 ft 4 in of bar, at 10 inches per standard bird. Several bars at different heights work fine; the dominant birds take the highest.
Does the run have to be 40 square feet?
That is the working minimum at 10 sq ft per standard bird. A run at the minimum will go to bare earth, which is normal rather than a failure. Keeping ground vegetated takes far more space — see how many square feet per chicken.
Sources
- Poultry Extension — space allowances for small and backyard flocks: 3 to 4 square feet of indoor space per hen plus about 10 square feet outdoors.
- Penn State Extension — small-scale poultry housing: outdoor minimums by bird type, which every run figure here meets or exceeds, and two nests for the first four hens.
- Virginia Cooperative Extension — small-scale poultry housing: roost length, published as 8 to 10 inches per bird.
Every figure on this page is produced by the same engine as the coop size calculator, where the sourcing for each is set out in full — including which are Flockmath planning conventions rather than published minimums. The 25% cold-climate adjustment and the ventilation figure are ours; the floor, run, nest-box and roost figures come from the extension sources above.
Figures are welfare minimums and planning guidance, not veterinary advice. Local zoning may cap flock size. Last reviewed August 2026.