Chicken Run Size Calculator
Chicken run and coop area from flock size.
What it does
Chickens need two footprints: indoor coop and outdoor run. Twelve hens want 120 sq ft of run at ten each with 36 to 48 sq ft of coop at three to four each. Crowding below either line buys pecking, disease, and cleaning loads.
The tool above runs extension space rules. Enter hens and it prints run area, the coop range, and metric run area. Six hens need 60 sq ft of run with 18 to 24 of coop; twenty need 200 with 60 to 80.
Three sources converge. UGA Madison County gives 3-3.5 sq ft of coop floor per layer, national extension tables set 3-4 indoor with 10 outdoor per hen, and the Merck Manual bands 1.5-2 indoor with 8-10 of run metrically. All three agree within rounding.
Covers and air finish housing beyond area. Hawk-proof run lids, ventilated draft-free coops, and dry bedding decide health as much as square feet. Small breeds squeeze slightly tighter; heavy breeds want the top of every range.
How to use
- Enter the hen count.
- Read run area first.
- Read the coop range.
- Convert the run mentally via m2.
- Cover runs; vent coops.
- Expand before crowding.
Formula
- hens
- Laying hens in the flock.
UGA 3-3.5 coop with extension 10-run rule; Merck metric bands (1.5-2 indoor, 8-10 run) corroborate.
Worked example
Example: 12 hens
Defaults: 12 hens.
- Input: 12 hens.
- Run: 12 x 10 = 120 sq ft.
- Coop: 12 x 3 to 12 x 4 = 36 to 48 sq ft.
- Metric: 120 / 10.7639 = 11.1 m2 run.
- Tool shows 120 sq ft run, 36 to 48 sq ft coop.
Reference table
| Hens | Coop | Run |
|---|---|---|
| 4 | 12-16 | 40 |
| 6 | 18-24 | 60 |
| 8 | 24-32 | 80 |
| 10 | 30-40 | 100 |
| 12 | 36-48 | 120 |
| 20 | 60-80 | 200 |
Limits
- Space math only. Predators need hardware.
- Breed size shifts needs within bands.
- Pasture rotation unmanaged.
- Local ordinances rule flock caps.
Common mistakes
- Counting coop as run space.
- Shrinking runs to fit yards.
- Skipping hawk covers.
- Sealing coops airtight.
- Adding birds past capacity.
Try it yourself
Quick checks. Answers sit tucked under each question.
6 hens?
Run 6 x 10 = 60 sq ft. Coop 18 to 24. Metric 5.6 m2.
20 hens?
Run 20 x 10 = 200 sq ft. Coop 60 to 80. Metric 18.6 m2.
Questions
How much run space?
Ten sq ft per hen outdoors. Here 120 sq ft, e.g. 10x12 ft.
How much coop space?
Three to four sq ft per hen indoors. Here 36 to 48, e.g. 6x8 ft.
What does Merck say metrically?
About 1.5-2 sq ft indoor with 8-10 sq ft of run per hen, consistent bands.
Do bantams need less?
Yes. Small breeds manage 3/4-1 sq ft indoors per UGA.
Covered run and vents?
Yes. Cover runs against hawks; ventilate coops without direct drafts.
What if space runs short?
Yes. Crowding spikes pecking, disease, and cleaning loads fast.
Sources
- UGA Extension: Backyard Layer Hens (3-3.5 coop)
- National Extension: Backyard Flock Space Allowances (3-4 + 10)
- Merck Vet Manual: Backyard Poultry (metric bands)