128 square feet is a 16-bird run, not a 25-bird run
The spec table says outdoor space for 16 to 25 hens. Those two numbers are doing very different jobs and it is worth being blunt about which one to build for.
At 16 birds, each hen gets 8 square feet. That is the number most extension services treat as the comfortable minimum for a run birds live in permanently — enough that they can get away from each other, dust-bathe without a fight, and keep the ground from being scratched down to bare dirt in a fortnight.
At 25 birds, each hen gets 5.1 square feet. That works if the flock is out on grass most of the day and this run is somewhere they sleep, shelter and wait out weather. Shut 25 birds in here full time and you will see the difference in the ground first and in the pecking order second.
If you are choosing between this and the 6x8 run at 48 square feet, the honest cut-off is nine birds. Below that the 6x8 is enough and saves you roughly $450. Above sixteen, look at the 10x20 rather than crowding this one.
What it costs against the sizes either side
| Run | Space | Comfortable / max | Materials |
|---|---|---|---|
| 6x8 | 48 sq ft | 6 / 9 hens | $850–$1,100 |
| 8x16 (this one) | 128 sq ft | 16 / 25 hens | $1,300–$1,700 |
| 10x20 | 200 sq ft | 25 / 40 hens | $1,900–$2,450 |
Going from the 6x8 to this one costs about $450 and buys 80 more square feet — roughly $5.60 a square foot. Going from here to the 10x20 costs another $600 for 72 square feet, or about $8.30 a square foot. The 8x16 is the best value per bird in the line, and that is not a coincidence: it is the size where a standard 8-foot stick of lumber stops being cut down and starts being used whole.
These figures come from this design’s own bill of materials — 17 line items, priced at 2026 rates with no waste allowance. Add two or three extra boards if you are new to framing.
The apron is most of the work and all of the point
Nothing in this plan matters as much as what happens at ground level. A run with walls and a roof and no buried apron is a box that a digging predator opens in one night.
Quarter-inch hardware cloth, extended out from the base and buried, is the whole argument. Half-inch mesh is the figure quoted everywhere and it genuinely stops raccoons — but a least weasel goes through anything a quarter-inch or larger, so half-inch does not deliver the exclusion most run plans imply. University of Kentucky Extension documents the mechanism directly in ID-245. The 12-inch apron depth is confirmed independently by Kentucky, Maryland and Florida extension services.
Budget your time accordingly: on a 192-inch by 96-inch perimeter you are trenching and burying roughly 48 running feet of mesh. That is most of a day on its own, and it is the day that decides whether the other three were worth it. Full detail in the predator-proofing guide.
At 72 inches you walk in — plan the door swing before you frame it
The run stands 72 inches at the eave with a 34-inch gate. That is walk-in for most adults, and it is the reason this design is worth its price over a low tractor-style run: you will be in here with a rake every week for years.
Two things people get wrong at framing time. The gate wants to swing out, not in, so a bird crowding the doorway does not get caught behind it. And the threshold wants to sit above the run surface, not flush with it, or every rake of bedding you pull toward the door goes over the sill and out.
Three to four days, and the roof is the part people underestimate
Twenty-two to thirty hours across three or four days, rated Intermediate rather than Beginner. The 6x8 is a one-weekend build; this one isn’t, and the difference isn’t the extra square footage.
It’s the span. At 192 inches long the roof needs framing that a 96-inch run doesn’t, and getting sheets up and fixed over a 72-inch-tall structure is two-person work for at least part of a day. Plan for a second pair of hands on the roof day even if you frame the rest alone.
The other time sink is the mesh, and it’s front-loaded in a way people don’t expect. Seventeen material line items sounds small until you notice how much of the build is repetitive fixing — mesh, washers, screws, over and over, around a perimeter and then overhead.
Set the posts against the ground you actually have
A run is more sensitive to siting than a coop is, because the floor is the ground and you don’t get to build it.
Walk the footprint after heavy rain before you commit. Water that sheets across the yard will sheet across the run, and a roof over standing water is still standing water. If the only flat ground you have collects, either raise the run surface with coarse sand or drain rock, or move it.
Get the posts square and plumb before anything else goes on. Everything after — the rails, the roof, the mesh, the gate — inherits whatever error is in the posts, and a run that’s out of square shows it most at the gate, which is the part you’ll use twice a day for years. The run design guide covers layout in more detail than the plan sheets do.
What it does to the ground underneath
Even at 8 square feet a bird, chickens will strip 128 square feet of grass. That isn’t a flaw in the design — it’s what a permanent run is. The question is whether you manage it or fight it.
Two approaches work. Either commit to a deep-litter surface — wood chips or coarse bedding, topped up and turned, which composts in place and keeps the surface dry — or accept bare earth and rake it. What doesn’t work is expecting grass to survive under a permanent flock at any stocking density worth building for.
A roof helps enormously here, which is the quiet argument for this design over an open run: dry ground stays workable, and wet ground turns to mud that stays mud. The cleaning guide covers litter management.
What this design deliberately does not do
It is not insulated, it has no floor, and it is not a coop. There is no nest box, no roost and nowhere for a bird to be warm overnight. If you were hoping to house birds in this alone, you want a coop-and-run set instead — the 8x8 walk-in is the closest equivalent with the same run footprint and somewhere for the flock to sleep.
It also does not solve mud on its own. A roof keeps rain off, but a run built in a low spot will still collect water running toward it. Site it on the highest ground you have, and read the run design guide before you set the first post.