Three 8x12 coops, three different buildings
We draw three coops on an 8 by 12 footprint, and they are not variations of each other. This one is the gable-roofed, all-coop version. The 8x12 walk-in shed coop puts a single-slope roof over a feed room and a smaller coop. The 8x12 insulated coop is that shed coop again, with a cold-climate envelope.
The difference that matters is where the floor goes. Here, all of the 8 by 12 box is bird floor: 80 square feet. The shed version gives three feet of length to feed storage and keeps 58 for the birds. If you have somewhere else to keep feed and bedding, a garage or a shed nearby, this design gives you 22 more square feet of coop for less money.
If you don’t, the feed room is worth more than it looks. Carrying feed sacks across the yard in the rain gets old fast.
What it costs against the walk-ins around it
| Design | Coop | Run | Hens | Walls | Materials |
|---|---|---|---|---|---|
| 8x10 walk-in | 66 sq ft | 96 sq ft | 12–14 | 76” | $3,700–$4,750 |
| 8x12 gable (this one) | 80 sq ft | 96 sq ft | 12–19 | 64-3/4” | $3,950–$5,050 |
| 10x10 walk-in | 84 sq ft | 120 sq ft | 15–17 | 76” | $4,150–$5,350 |
| 8x12 walk-in shed | 58 sq ft | 128 sq ft | 14–18 | 76” | $4,250–$5,450 |
| 8x16 walk-in | 79 sq ft | 160 sq ft | 19–26 | 76” | $4,950–$6,400 |
By coop floor per dollar, this and the 10x10 are the two best buys in the walk-in range, both around $49-$64 a square foot. The 8x12 shed coop runs about $73-$94 a square foot, because part of its building is a feed room.
The row to study is the 10x10. For $200-$300 more you get 4 more square feet of coop, 24 more of run and 76-inch walls, at a lower rated head count of 17. It needs a 10-foot-wide spot instead of 8. If your yard has the width, compare those two carefully before you choose.
The gable is tall; the room is not
This is the most important thing to understand about this design, and the spec table doesn’t show it.
The roof is a 12:12 gable. The rise equals the run, so the ridge lands 48 inches above the top plate and the peak stands 153-5/16 inches high. From outside it looks like a big building.
Inside, the walls are 64-3/4 inches. Every opposing rafter pair is tied across the width at top-plate level, seven ties in all, because a pitched roof pushes its walls outward and the ties are what resist that. Those ties cross the room at about wall height. So the usable standing height is set by the ties, not the ridge, and most adults will stoop.
The door opening is 34 by 62-3/4 inches, cut into the front wall. You walk in with a rake and a bucket, and you work bent under the ties. If you want to stand straight up to clean, look at the 76-inch walls on the shed-roof walk-ins. The walk-in coop guide covers what “walk-in” usually means and where designs fall short of it.
Two feet off the ground, on purpose
The floor sits 24 inches off grade. That is higher than any other coop we draw. Our shed walk-ins sit at 12 inches and the small reach-ins at 14 to 20.
The height buys three things. The frame stays well clear of ground moisture. It clears the 18-inch figure often given for places with established rat pressure, which a 12-inch floor does not. And it leaves a full 8 by 12 patch of shaded, dry ground under the coop, closed in with 27 feet of hardware-cloth skirt, that the flock will use on every hot afternoon.
The cost is getting in. The pop-door sill sits 34-1/4 inches above grade, and on a level site the plan’s ramp runs about 69-7/8 inches with a cleat every 4 inches. The people door is a big step up from the ground, so plan a solid step or a small landing outside it. You will use it every day.
Nineteen is the coop’s number, not the run’s
At 12 hens each bird gets 6.7 square feet of coop floor. At 19 it drops to 4.2, still above the 3-4 square feet per bird extension services publish for a coop with a run.
The roost matches the top figure. Nineteen birds need 190 inches of perch at 10 inches each, and the plan builds 219 inches, three 73-inch bars on edge with a leg under each at mid-span. Five exterior nest boxes on a 74-1/2 inch bank give one box per 3.8 hens at 19.
The run is the tight part. 96 square feet is 8 square feet a bird at 12, and 5.1 at 19. If your flock lives in the run full time, stock this coop at 12 to 14. The extra coop floor then becomes winter space rather than day-to-day space, which is a fine way to use it. Run your own numbers in the size calculator.
Seven to nine days, and plan the roof day
55-70 hours, 18 steps, 35 material line items, rated Advanced. The walls are framed flat on the deck and stood up. The gable is where the time goes: 14 rafters, each cut at 45 degrees, a ridge board, seven ties and gable studs cut to fit under each rafter.
Working 24 inches off the ground with a ridge nearly 13 feet up means scaffolding or solid ladders on the roof day, and a second person for the roof panels. The corrugated metal comes in 8-foot sheets, one piece from eave to ridge.
Check the rules before you order lumber. The coop alone is 96 square feet of footprint, and the full length with the run is 288 inches, around 192 square feet of ground. That sits under the 200 square feet IRC R105.2 exempts, but roughly half of adopting jurisdictions tighten that to 100, 120 or 144. Some also cap the height of accessory buildings, so ask about the ridge while you are asking. The permit guide explains how those rules usually work.
What this design deliberately does not do
It has no feed room. Feed, bedding and tools live somewhere else.
It has no full-height interior. The walls are 64-3/4 inches and the ties sit at that level.
It is not insulated. Ventilation is a permanently open strip along the top of the back wall, 5-1/2 by 134 inches or 5.1 square feet, screened with hardware cloth, plus four windows that get cloth behind the glass. Don’t close the strip in winter. A coop sealed against the cold traps the moisture 19 hens breathe out, and University of Minnesota Extension ties frostbite to moisture combined with cold, not cold alone.