Coop Size Guide
Chicken Coop Size for 20 Hens
Twenty hens is a serious smallholding flock — the numbers scale simply, but the setup needs planning like one.
The short answer: 70–80 sq ft of coop
At 3.5–4 sq ft of coop floor per standard hen, 20 hens need 70–80 sq ft. The natural buildable footprint is 8 × 10 ft — exactly 80 sq ft, with enough depth to walk in, which stops being a luxury and becomes a necessity when you are cleaning up after 20 birds in winter.
The full plan for 20 hens:
| Item | For 20 hens |
|---|---|
| Coop floor | 70–80 sq ft (suggested build: 8 × 10 ft) |
| Run | 200 sq ft (e.g. 10 × 20 ft) |
| Roost bar | ~20 ft in total (e.g. two 10 ft bars) |
| Nesting boxes | 5–7 |
Run space is calculated at 10 sq ft per hen, roost at about 1 ft per bird, and nesting boxes at one per 3–4 hens — the planning figures behind every FlockCalc calculator.
Layout at this scale: think in zones
In an 8 × 10 coop the floor plan starts to matter as much as the floor area. Keep the roosts along one long wall, the nesting boxes along another, and feed and water near the door where you can reach them without crossing the whole building. That zoning keeps droppings concentrated under the roosts — where you can put a droppings board or your deepest litter — and keeps eggs out of the traffic.
The 10-hen coop guide shows the same zoning logic at half the scale; everything there doubles cleanly to this flock, because the per-hen rates do not change — only the totals do.
200 sq ft of run, and how to keep it alive
Twenty hens need about 200 sq ft of run at 10 sq ft per bird. Bare area is not the whole story at this flock size: 20 hens will strip 200 sq ft of grass in a season if they are on it full-time. The setups that survive divide the run in two and rotate the flock between halves, so each side gets weeks of rest and regrowth.
Whether you rotate or not, the Chicken Run Size Calculator turns the 200 sq ft into dimensions for your plot and the fencing length to enclose it — at this size, fencing is a real line in the budget and worth measuring before you buy.
Roosts and boxes for 20
About 20 ft of roost is the figure — most simply two 10 ft bars at the same height along the long wall. Same height matters more as the flock grows: a stepped roost creates a nightly contest for the top bar, and with 20 hens that contest has 20 contestants. Keep the bars above the nesting boxes so the boxes stay sleeping-free.
Nesting boxes run 5–7 for 20 hens at one per 3–4 hens. Err towards six: enough that a queue never forms at peak laying, few enough that you are not cleaning boxes nobody uses. The Nesting Box & Roost Calculator works both numbers out from any flock size.
What changes when the flock is 20
Space is the planning question, but labour is the daily one. Twenty hens eat, drink and produce droppings at twenty-hen rates, and the keepers who enjoy a flock this size are the ones who sized the whole system — coop, run, storage, cleaning access — to the same honest numbers. The rates behind this page are the same ones in our guide to how much space chickens really need; they do not get more generous as flocks grow, and neither does the work of fixing an undersized build.
Frequently asked questions
How big should a coop be for 20 chickens?
Plan on 70–80 sq ft of coop floor: 20 hens × 3.5–4 sq ft each. An 8 × 10 ft coop gives exactly 80 sq ft and is the standard buildable footprint at this size; a 7 × 10 ft coop at 70 sq ft covers the lower end.
How much run space do 20 hens need?
About 200 sq ft — 10 sq ft per hen. Think 10 × 20 ft, or a longer strip you can divide and rotate so the ground gets a rest.
How many nesting boxes and how much roost for 20 hens?
Five to seven nesting boxes (one per 3–4 hens) and about 20 ft of roost bar (about 1 ft per bird), most practically built as two 10 ft bars at the same height.
Can 20 hens share one coop, or should they be split?
One coop of 70–80 sq ft houses 20 hens comfortably as a single flock, and one flock is simpler to feed, water and clean up after than two. Splitting only helps if the birds genuinely do not get on, or if you are running separate breeding groups.
The bottom line
For 20 hens, build 70–80 sq ft of coop — 8 × 10 ft is the standard fit — with 200 sq ft of run, about 20 ft of roost across two bars, and 5–7 nesting boxes. Scale the whole system to the flock, and a 20-hen setup runs as smoothly as a 6-hen one.