Coop Size for 4, 6, 8, 10 and 12 Hens (Worked Examples)

Rules of thumb are easy to state and easy to get wrong when you apply them. This page works through five complete examples, for 4, 6, 8, 10 and 12 standard laying hens with a run, using the same method as the CoopSizer calculator. Every step is written out, so you can check the math or redo it with your own figures.

The figures used

All rates come from university extension guidance, taking the upper end where the sources differ. The reasoning behind each one is in how much space chickens need.

Coop floor: 4 sq ft per standard hen (range 1.5 to 4) Run: 10 sq ft per standard hen (range 2 to 10) Roost: 8 in per hen (range 5 to 10) Nest boxes: 1 per 4 hens, rounded up, at least 2 Winter inlet: 6 sq in per 25 sq ft of floor (Kentucky AEN-161) Ridge gap: 3 in per 10 ft of width (Kentucky AEN-161) Summer windows: about 18% of the floor (Kentucky AEN-161)

The coop footprint is the smallest of these standard sizes that covers the floor needed: 3 x 4, 4 x 4, 4 x 6, 4 x 8, 6 x 8, 8 x 8, 8 x 10, 8 x 12 feet and up. They work with 4 x 8 foot sheet goods, so there is less waste. The run is fenced in widths of 4, 6, 8 or 10 feet and lengths in 2 foot steps.

4 hens

Coop: 4 x 4 sq ft = 16 sq ft -> 4 x 4 ft (16 sq ft) Run: 4 x 10 sq ft = 40 sq ft -> 4 x 10 ft (40 sq ft) Roost: 4 x 8 in = 32 in = 2.7 ft -> 1 bar, 3.5 ft usable Nests: 4 / 4 = 1 -> minimum 2 Winter inlet: 16 x 6 / 25 = 3.8 sq in Summer windows: 16 x 0.18 = 2.9 sq ft

A 4 x 4 coop is a reach-in coop: you clean it through doors, not by walking in. Make sure at least one whole side opens.

6 hens

Coop: 6 x 4 sq ft = 24 sq ft -> 4 x 6 ft (24 sq ft) Run: 6 x 10 sq ft = 60 sq ft -> 6 x 10 ft (60 sq ft) Roost: 6 x 8 in = 48 in = 4 ft -> 2 bars of 3.5 ft Nests: 6 / 4 = 1.5 -> 2 Winter inlet: 24 x 6 / 25 = 5.8 sq in Summer windows: 24 x 0.18 = 4.3 sq ft

One 3.5 foot bar would hold 42 inches, short of the 48 needed, so the plan uses two bars.

8 hens

Coop: 8 x 4 sq ft = 32 sq ft -> 4 x 8 ft (32 sq ft) Run: 8 x 10 sq ft = 80 sq ft -> 8 x 10 ft (80 sq ft) Roost: 8 x 8 in = 64 in = 5.3 ft -> 2 bars of 3.5 ft Nests: 8 / 4 = 2 -> 2 (Penn State's rule would give 3) Winter inlet: 32 x 6 / 25 = 7.7 sq in Summer windows: 32 x 0.18 = 5.8 sq ft

The 4 x 8 is the classic backyard coop because the floor is exactly one sheet of plywood. For eight standard hens it is a precise fit, with no spare room. If you think the flock might grow, or you keep large breeds, step up to 6 x 8.

10 hens

Coop: 10 x 4 sq ft = 40 sq ft -> 6 x 8 ft (48 sq ft) Run: 10 x 10 sq ft = 100 sq ft -> 10 x 10 ft (100 sq ft) Roost: 10 x 8 in = 80 in = 6.7 ft -> 2 bars of 5.5 ft Nests: 10 / 4 = 2.5 -> 3 Winter inlet: 48 x 6 / 25 = 11.5 sq in Ridge gap: 3 x 6 / 10 = 1.8 in Summer windows: 48 x 0.18 = 8.6 sq ft

Forty square feet does not match a standard footprint, so the next size up, 6 x 8, gives 48. Above 32 square feet the calculator assumes 6 foot walls, so you can step inside to clean, which also raises the panel count.

12 hens

Coop: 12 x 4 sq ft = 48 sq ft -> 6 x 8 ft (48 sq ft) Run: 12 x 10 sq ft = 120 sq ft -> 10 x 12 ft (120 sq ft) Roost: 12 x 8 in = 96 in = 8 ft -> 2 bars of 5.5 ft Nests: 12 / 4 = 3 -> 3 Winter inlet: 48 x 6 / 25 = 11.5 sq in Summer windows: 48 x 0.18 = 8.6 sq ft

The same 6 x 8 coop holds ten or twelve standard hens; the difference is the run and the roost length. A thirteenth hen needs 52 square feet, which means an 8 x 8.

All five side by side

Hens	Coop	Run	Roost	Nests	Materials (cold climate)
4	4 x 4 ft	4 x 10 ft	2.7 ft	2	$480 to $1,540
6	4 x 6 ft	6 x 10 ft	4 ft	2	$580 to $1,860
8	4 x 8 ft	8 x 10 ft	5.3 ft	2	$680 to $2,170
10	6 x 8 ft	10 x 10 ft	6.7 ft	3	$860 to $2,750
12	6 x 8 ft	10 x 12 ft	8 ft	3	$900 to $2,880

The materials column is an estimate, not a quote. It multiplies counted quantities by wide assumed price ranges and includes optional roof insulation for a cold climate. Verify at your local store. The method is in how much a DIY coop costs.

What changes with bigger or smaller birds

Eight hens again, with different bird sizes:

8 bantams: coop 8 x 3 = 24 sq ft -> 4 x 6 ft; run 8 x 8 = 64 sq ft -> 8 x 8 ft 8 large: coop 8 x 5 = 40 sq ft -> 6 x 8 ft; run 8 x 12 = 96 sq ft -> 8 x 12 ft

Going from bantams to large breeds moves eight hens from a 4 x 6 coop to a 6 x 8. With no run at all, size on 8 to 10 square feet per bird inside (Oregon State).

Before you build

Check your town's flock limit, rooster rules and setbacks. The Kentucky urban guide lists towns that require the coop to be 50 feet or more from a neighbor's house.
Decide on the final flock size, then add room. Spring makes it easy to bring home extra chicks.
Plan the run and the predator mesh at the same time as the coop. See hardware cloth vs chicken wire.

Every example on this page came from the coop calculator. Put in your own numbers and it draws the plan to scale.

Frequently asked questions

What size coop do I need for 6 chickens?

About 24 square feet of coop floor for six standard hens with a run, which is a 4 by 6 foot coop, plus a run of about 60 square feet, such as 6 by 10 feet.

Is a 4 by 8 coop big enough for 8 chickens?

Yes for eight standard hens with a run: 8 times 4 square feet is 32 square feet, exactly a 4 by 8. For eight large-breed hens at 5 square feet each you need 40, so step up to 6 by 8.

How many nest boxes for 10 or 12 hens?

Three. Ten or twelve divided by four is 2.5 or 3, rounded up to 3.

Why is the run so much bigger than the coop?

Because extension figures for the run are larger: about 10 square feet per laying hen outside, compared with 3 to 4 inside.

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Get the printable coop checklist

One page to take to the lumber aisle and the build site. Every number on it comes from university extension guidance, with the source named.

Floor space per hen, coop and run
Roost inches, height and spacing
Nest boxes: count, size, height
Vent areas for winter and summer
Hardware cloth, apron and night lockup
Ordinances and setbacks to check first