Chicken brooder size calculator
Quick answer: Penn State Extension sets brooder minimums at 1/4 sq ft per chick the first week, 1/2 sq ft at 2 to 3 weeks, 3/4 sq ft at 3 to 5 weeks and 1 sq ft at 5 to 8 weeks. University of Maine Extension uses 0.5 sq ft per chick through 4 weeks, then 1 sq ft to 8 weeks.
Brooder size calculator
The square-box dimension is simple geometry (square root of the floor area), shown so you can picture it. Any shape with the same floor area works.
Penn State Extension brooder table
| Age | Min. floor space (sq ft per bird) | Max. temperature |
|---|---|---|
| 1st week | 0.25 | 92–95°F |
| 2–3 weeks | 0.5 | 85–90°F |
| 3–5 weeks | 0.75 | 80–85°F |
| 5–8 weeks | 1.0 | 70–80°F |
Source: Penn State Extension, Space Should Increase as Birds Grow.
University of Maine Extension table
| Age | Floor (sq ft per bird) |
|---|---|
| 0–4 weeks | 0.5 |
| 4–8 weeks | 1.0 |
| 8–12 weeks | 2.0 |
Source: University of Maine Cooperative Extension Bulletin #2219, Table 1.
Why the two tables differ
Penn State starts smaller and steps up every week or two. Maine uses wider age bands. The calculator shows both so you can choose; this page does not average them. Penn State also says to warm the brooding area to 92°F at least 24 hours before the chicks arrive.
Once birds move to the coop, see coop size by flock and the full poultry space requirements data.