The most bird floor in the walk-in family
Every walk-in plan larger than this one gives some of its length to a feed room. This is the biggest design in the family that doesn’t. All 84 square feet of coop floor belongs to the birds.
That puts the 10x10 ahead of plans that are bigger buildings. The 10x12 walk-in gives its birds 74 square feet. The 8x16, the longest coop on the site, gives 79. The 8x12 gives 58. If your measure of a coop is how much floor the hens actually stand on, nothing in the line beats this one.
The trade is the obvious one. There’s no dry room at the door for feed bins, a bedding bale and tools. Those live in your garage, your shed or a lidded can beside the run. For a lot of people that’s already where they are, and the feed room is money spent on a closet they don’t need.
Cheapest per square foot, not cheapest per hen
Two different ways of pricing a coop give two different winners, and it’s worth knowing which one you care about.
Per square foot of coop floor, the 10x10 is the best value of any walk-in plan. At the low end of its materials range it works out to about $49 a square foot. The 8x10 is about $56, the 8x8 about $63, the 10x12 about $64 and the 8x12 about $73.
Per hen of capacity, it isn’t. At 17 birds the 10x10 costs about $244 a hen at the low end. The 10x12 is about $214 and the 8x16 about $190, because those plans carry more roost, more nest boxes and much bigger runs and so are rated for more birds.
So the 10x10 is the right buy when you want generous space for a flock of fifteen or so, not when you’re trying to house the most birds per dollar. The cost breakdown guide prices every plan off its own material list if you want to run the comparison further.
What it costs against its neighbors
| Plan | Coop floor | Run | Hens | Feed room | Build time | Materials |
|---|---|---|---|---|---|---|
| 8x10 walk-in | 66 sq ft | 96 sq ft | 12–14 | No | 46–58 hrs | $3,700–$4,750 |
| 10x10 walk-in (this one) | 84 sq ft | 120 sq ft | 15–17 | No | 60–78 hrs | $4,150–$5,350 |
| 8x12 walk-in | 58 sq ft | 128 sq ft | 14–18 | Yes | 60–75 hrs | $4,250–$5,450 |
| 10x12 walk-in | 74 sq ft | 160 sq ft | 18–22 | Yes | 75–95 hrs | $4,700–$6,000 |
The 10x10 and the 8x12 sit $100 apart and take about the same time to build. That’s the real choice at this price. One gives the birds 26 more square feet of coop. The other gives you a feed room and 8 more square feet of run.
Coming up from the 8x10, the step costs $450-$600 and adds 18 square feet of coop, 24 of run and three hens at the top end. It also adds about two build days, which is the part people forget to budget.
Fifteen to seventeen, with room left over
The plan caps capacity at 17, and it’s the fittings that set that number, not the floor.
At 17 hens each bird has 4.9 square feet of coop. That’s well past the 3-4 square feet Oregon State and Virginia Tech publish for a coop with an attached run. The run gives 7.1 square feet a bird, a little under the 8-10 square feet extension services recommend outdoors. 170 inches of roost is exactly 10 inches a hen, and five nest boxes is one per 3.4 birds.
At 15 hens the coop gives 5.6 square feet each and the run exactly 8, which brings the outdoor number inside the published range.
That spare indoor floor is the design’s real advantage. It’s what makes a week of ice storms or a heat wave with the birds shut in bearable. It’s room for a temporary broody pen or a crate for a bird you’re watching, without crowding everyone else. Coops rated right at their floor limit have none of that. The size calculator shows how fast the margin disappears in smaller designs.
220 square feet of ground crosses the IRC line
This is the first plan on this end of the family where the permit question probably flips.
The enclosed coop is 100 square feet nominal, sitting exactly on the strictest local exemption thresholds. Coop and run together are 264 inches by 120, about 220 square feet of ground. The IRC’s R105.2 exemption for detached accessory structures stops at 200. If your jurisdiction counts the run as part of the structure, you’re over it even before any local tightening.
A permit isn’t a reason not to build. It’s a reason to call the building department before you buy materials, not after a neighbor calls them for you. Setbacks are zoning rather than building code, and a 10-foot-wide building uses more of a side setback than an 8-foot one. The permit guide covers what to ask.
A size class up in the build, too
Going from 8 feet wide to 10 changes more than the floor. The material list grows to 35 line items, and several of them are new to this plan:
- Seventeen 4x4 posts on 16 pier blocks, against 12 blocks on the 8x10. Sixteen blocks to set level over a 22-foot footprint is its own half day.
- 2x8 header stock, which none of the smaller walk-ins call for.
- Thirteen sheets of 3/4-inch plywood and 43 pieces of siding covering about 293 square feet of wall.
- 12-foot corrugated roof panels, six of them. A 12-foot metal sheet on a ladder is not a one-person lift.
- 188 feet of quarter-inch hardware cloth and 752 fender washers, plus two cubic yards of sand or drain rock for the run floor.
The plan budgets 60 to 78 hours over eight to ten days. It’s rated Advanced, and the scale is most of the reason.
Climate: a big room with no insulation
This is a lot of air for a flock of seventeen to heat with their own bodies, and the design is uninsulated. It carries 5.5 square feet of permanent vent and four windows.
In mild and warm climates that’s a strength. A big volume of moving air handles summer heat better than a tight small coop. In serious winter country it’s the wrong building to insulate after the fact. The site’s cold-climate design is the 8x12 insulated coop, rated 14-18 hens at $5,500-$7,100.
If your winters are only occasionally hard, the spare floor here does more for the birds than insulation would. They can spread out, stay off each other and stay dry.
Who should build the 10x10
Someone keeping fifteen or sixteen hens who wants them to have real room, with feed storage already solved somewhere else on the property. It suits a builder who has framed before and has a helper for roof day, and a site with about 10 by 22 feet of ground that can be leveled.
It’s the wrong pick if the goal is the most birds per dollar. The 10x12 and 8x16 both house more hens for less per bird. It’s also the wrong pick if you’d be hauling feed across the yard in the rain every morning and would rather not. The 8x12 costs $100 more and puts the bins inside the door.