Duck coop size works out to 3 to 5 sq ft of floor per duck (Penn State says 3, the poultry extension network says 5) and about 15 sq ft of run per duck, so a house for 6 ducks is 18 to 30 sq ft of floor with a 90 sq ft run, and a house for 8 is 24 to 40 sq ft with 120 of run. Enter your count below, pick where in that range you want to land, and the calculator gives you house floor, run area, nest count and which of our two duck plans fits.
Ducks are not chickens with webbed feet, and a chicken calculator gives you the wrong house. A duck doesn’t roost, so every inch of the house is floor and there’s no vertical space to borrow. A duck carries water out of the drinker on its bill and down its chest every time it drinks, so the floor around the water is wet all day. And a duck lays on the floor, so the nest sits on the floor, not up a wall. The numbers below are built around those three facts.
The sizing table
| Ducks | Floor at 3 sq ft (Penn State) | Floor at 5 sq ft (poultry.extension.org) | Run at 15 sq ft | Our plan | Plan floor | Plan run |
|---|---|---|---|---|---|---|
| 2 | 6 sq ft | 10 sq ft | 30 sq ft | 4x6 duck house | 16 sq ft | 48 sq ft |
| 4 | 12 sq ft | 20 sq ft | 60 sq ft | 4x6 duck house | 16 sq ft | 48 sq ft |
| 6 | 18 sq ft | 30 sq ft | 90 sq ft | 6x8 duck house | 37 sq ft | 96 sq ft |
| 8 | 24 sq ft | 40 sq ft | 120 sq ft | 6x8 duck house | 37 sq ft | 96 sq ft |
| 10+ | 30+ sq ft | 50+ sq ft | 150+ sq ft | no plan yet |
Read the two floor columns as a range, not a choice. Penn State’s 3 sq ft is a night-only number for ducks that are out all day. The 5 sq ft figure is what the national poultry extension network recommends and is the one to use if the ducks will ever be shut in for a day, which in most climates they will.
How our two plans score against it
The 4x6 duck house is 16 sq ft of floor and a 4x12 run of 48 sq ft, rated 3 to 4 ducks. At four ducks that’s 4 sq ft of floor each, dead center of the range, and 12 sq ft of run each, which is under Penn State’s 15. At three ducks it’s 5.3 and 16, over both figures. If the ducks have a yard, four is fine; if the run is their whole world, build it for three.
The 6x8 duck house is 37 sq ft of floor and a 6x16 run of 96 sq ft, rated 6 to 8. At eight ducks: 4.6 sq ft of floor each, 12 of run. At six: 6.2 of floor, 16 of run. Same pattern: the top of the rating meets the middle of the floor range and comes in 3 sq ft short on the run. We’d call the 6x8 a six-duck house with room for two more if they free-range.
We don’t have a plan past 8 ducks and the calculator will tell you so rather than stretch the 6x8.
Why the run number matters more for ducks
Penn State gives ducks 15 sq ft outside against 10 for a large chicken, and the reason is water. Ducks need water deep enough to dunk their heads, and whatever you give them they’ll splash most of it onto the ground. A run that’s too small becomes mud in a week. Keep the tub in the run, never in the house, and put it on the far end from the door so the wet patch isn’t the one you walk through. Our duck plans mark a drip zone inside for the drinker and line the floor, because even with the pool outside, the drinker spot stays damp.
Nests and ventilation
Ducks lay early, often before you let them out, and they lay where they are, so a floor-level nest at the back of the house catches most eggs. Our plans use one nest per two ducks (two on the 4x6, four on the 6x8). That’s our ratio, not an extension figure; no university sheet we checked gives a ducks-per-nest number, so we erred generous.
Ventilation is the other thing a duck house needs more of. Wet bedding means ammonia, and a house that’s fine for hens will smell with ducks. The 4x6 carries 3.4 sq ft of permanent vent for 16 sq ft of floor and the 6x8 carries 4.8 for 37, both well over the 1-per-10 ratio our chicken plans use (which is our own default, not a published standard). The ventilation guide covers where the openings go.
Predators
A duck on the ground at night is an easier meal than a hen on a roost. Both duck houses sit on an 8-inch raised floor with quarter-inch, 19-gauge hardware cloth on every opening (the 6x8 takes 162 feet of it, run included) and a 12-inch apron buried down and out around the run. Oregon State’s bulletin says to bury run fencing 6 to 12 inches, so the plan sits at the deep end of that. The predator-proof guide explains both.
If you keep ducks and chickens together, size for the ducks and let the hens use the roost space the ducks ignore. The chicken coop size calculator handles the chicken half.