Chicken Coop & Run Calculator
How much coop and run a flock actually needs, plus nesting boxes, roost length, feeder and water, and how long a bag of feed lasts, all worked from US cooperative extension guidelines. More room is always better, so treat these as minimums.
For 6 standard hens, plan at least 21 sq ft of coop floor and 60 sq ft of fenced run, plus 2 nest boxes and about 4.5 ft of roost.
Check a coop you are planning
How to use it
- Enter the flock size. Enter the number of hens and choose bantam, standard, or large breed size.
- Choose the outdoor setup. Pick a fenced run or free-range pasture, then choose the winter and summer conditions.
- Check a planned coop. If you already have dimensions, enter the planned coop and run area to compare them with the minimums.
- Read the flock plan. Use the results for coop floor, run size, nest boxes, roost, feeder, water, feed, and bag life.
How the numbers are set
Coop floor space scales with flock size: about three and a half square feet per standard hen with access to a run, one for a bantam, four for a heavy breed. Run space is about ten square feet per hen, far more for genuine free-range pasture. Nesting boxes run one per four hens, roosts about eight to ten inches of bar per bird, feeders about three inches of trough each. A laying hen eats roughly a quarter pound of feed and drinks about a pint of water a day, and in hot weather she drinks twice that.
Ventilation and winter, honestly
There is no single per-bird ventilation number worth trusting. The rule that works: vent high near the roofline, keep it draft-free down at roost level, and if windows or walls show condensation in the morning, add more. Moisture, not cold, is what harms chickens. Most standard backyard breeds are cold-hardy and do not need a heated coop, and extension services widely discourage coop heaters as a fire risk. The one winter add-on worth it is a heated waterer, because water freezes at 0 °C and birds cannot drink ice.
Sources
Space, perch, feeder, feed and water figures come from Cornell Cooperative Extension, University of Maryland Extension, Penn State Extension, University of Minnesota Extension, University of Georgia Extension, Alabama Cooperative Extension, and poultry.extension.org. Pasture stocking follows Certified Humane. Ranges are given where extensions disagree; roost length spans six to twelve inches per bird, and there is no agreed temperature for supplemental heat.
Chicken coop questions
How much coop space does each chicken need?
This calculator uses about 3.5 square feet of coop floor for each standard hen with run access, 1 square foot for a bantam, and 4 square feet for a large breed. Treat those as minimums, not comfort targets.
How much run space should I plan?
The fenced-run setting uses 10 square feet per hen. The free-range setting uses 108 square feet per hen, which is a much larger pasture-style allowance.
How many nest boxes do hens need?
The page uses one nest box for every four hens, rounded up. Six hens therefore need 2 nest boxes, and 12 hens need 3.
How much roost space is enough?
The calculator uses 9 inches of roost bar per bird, inside the common extension range of about 6 to 12 inches per bird.
How much feed and water does a hen use?
A laying hen is estimated at about 0.25 lb of feed and 1 pint of water per day. In hot weather, the water estimate doubles.