Chicken Coop Size by Flock Calculator
Size a coop and run for your flock from the number of birds and their breed size, with recommended interior area, outdoor run area and nesting boxes.
How it works
Coop area = birds × per-bird coop ft² · Run area = birds × per-bird run ft² · Nesting boxes = ceil(birds ÷ 4)
Chickens crowded below their minimum space get stressed, and stressed hens peck, bully and spread disease faster, so the per-bird figures are floors to exceed rather than targets to hit exactly. Standard laying breeds want roughly 4 square feet each inside the coop and about 10 in the run; bantams need less and heavy breeds more. You do not need a nesting box per hen — one box for every three to four birds is plenty since they share and take turns — but you do need enough roost bar, around 8 inches per bird, so everyone can perch off the floor at night.
Worked example
Six standard hens need 6 × 4 = 24 sq ft of coop floor (about a 4.9 × 4.9 ft coop) and 6 × 10 = 60 sq ft of run. That works out to 2 nesting boxes and roughly 48 inches (4 ft) of roost bar.
Frequently asked questions
How much space does one chicken really need?
For standard breeds, plan on at least 4 square feet inside the coop and 8–10 square feet in the run per bird. If the birds are confined most of the day rather than free-ranging, err toward the larger end to prevent boredom and feather-picking.
How many nesting boxes do I need?
About one box for every three to four hens. Hens queue for a favourite box regardless of how many you provide, so extra boxes beyond that ratio mostly go unused — better to spend the space on floor area and roosting.
Can I keep more birds in a smaller coop?
It is strongly discouraged. Overcrowding raises ammonia from droppings, spreads parasites and disease, and triggers aggressive pecking that can injure or kill birds. If space is tight, keep fewer chickens rather than squeezing the flock in.
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This calculator is for educational purposes. Double-check important results before acting on them.