How this calculator works
For outdoor-access housing, this planner uses 4 ft2 indoors and 10 ft2 of run per standard hen from poultry extension guidance. Bantams use the Maryland extension minimum of 1 ft2 indoors and 4 ft2 outside. These references describe different minimum management conditions, not a guarantee of welfare. Mostly-indoor mode requires your own allowances. Free-range mode reports shelter area without sizing a fenced run.
Formula
coop area = standard birds x standard allowance + bantams x bantam allowance; run area = standard birds x 10 ft2 + bantams x 4 ft2.
Worked example
Ten standard hens with run access give 40 ft2 (3.716 m2) indoors and 100 ft2 (9.290 m2) outside. Four bantams give 4 ft2 indoors and 16 ft2 of run.
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Frequently asked questions
Is equipment space included?
Use genuinely available floor space. Feeders, nest boxes and inaccessible corners can reduce the area available to the birds.
Should a winter coop be larger?
Birds confined for long periods may need more space and enrichment. Use a husbandry plan suited to your climate and flock.
Does free range remove the need for a coop?
No. Birds still need suitable shelter, roosts, predator protection and ventilation.