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Chicken coop size by flock size
One set of extension rates covers every standard flock on this site. The old per-count pages multiplied those same rates and stopped there. This page keeps the counts, shows the multiplication once, and separates the minimum from the planning floor.
Size a count with the site calculator
The form calls calcCoopSize and calcNestBoxes in assets/app.js, the same functions the homepage calculator uses. The math in that file is unchanged.
Read the two results as different jobs. The table below multiplies the published rates exactly (4 and 10 for standard hens). The calculator uses those same 4 and 10, then rounds the coop up to the next 2 sq ft and the run up to the next 4 sq ft. For bantams the calculator uses 2 sq ft indoors and 8 sq ft of run, which is above the Penn State and Maryland minimum of 1 and 4. Nest boxes on the calculator are 1 per 3 hens, tighter than the published 1 per 4 to 5.
Full table: standard hens
Counts covered: 3, 4, 5, 6, 8, 10, 12, 15, 20, 25, 30, and 50. Six hens also have their own page for prefab labels and the free-range question: how big a coop should be for 6 hens.
| Flock | Coop, ×4 sq ft | Indoor minimum, ×1.5–2 | Run, ×10 sq ft | Laying-hen run, ×8 sq ft | Nests, 1 per 4–5 | Penn State nests | Feed / week | Example coop | Example run |
|---|---|---|---|---|---|---|---|---|---|
| 3 | 12 sq ft | 4.5 to 6 sq ft | 30 sq ft | 24 sq ft | 1 | 2 | 9 lb | 3 × 4 ft | 5 × 6 ft |
| 4 | 16 sq ft | 6 to 8 sq ft | 40 sq ft | 32 sq ft | 1 | 2 | 12 lb | 4 × 4 ft | 5 × 8 ft |
| 5 | 20 sq ft | 7.5 to 10 sq ft | 50 sq ft | 40 sq ft | 1 to 2 | 3 | 15 lb | 4 × 5 ft | 5 × 10 ft |
| 6 | 24 sq ft | 9 to 12 sq ft | 60 sq ft | 48 sq ft | 2 | 3 | 18 lb | 4 × 6 ft | 6 × 10 ft |
| 8 | 32 sq ft | 12 to 16 sq ft | 80 sq ft | 64 sq ft | 2 | 3 | 24 lb | 4 × 8 ft | 8 × 10 ft |
| 10 | 40 sq ft | 15 to 20 sq ft | 100 sq ft | 80 sq ft | 2 to 3 | 4 | 30 lb | 5 × 8 ft | 10 × 10 ft |
| 12 | 48 sq ft | 18 to 24 sq ft | 120 sq ft | 96 sq ft | 3 | 4 | 36 lb | 6 × 8 ft | 10 × 12 ft |
| 15 | 60 sq ft | 22.5 to 30 sq ft | 150 sq ft | 120 sq ft | 3 to 4 | 5 | 45 lb | 6 × 10 ft | 10 × 15 ft |
| 20 | 80 sq ft | 30 to 40 sq ft | 200 sq ft | 160 sq ft | 4 to 5 | 6 | 60 lb | 8 × 10 ft | 10 × 20 ft |
| 25 | 100 sq ft | 37.5 to 50 sq ft | 250 sq ft | 200 sq ft | 5 to 7 | 8 | 75 lb | 10 × 10 ft | 10 × 25 ft |
| 30 | 120 sq ft | 45 to 60 sq ft | 300 sq ft | 240 sq ft | 6 to 8 | 9 | 90 lb | 10 × 12 ft | 15 × 20 ft |
| 50 | 200 sq ft | 75 to 100 sq ft | 500 sq ft | 400 sq ft | 10 to 13 | 14 | 150 lb | 10 × 20 ft | 20 × 25 ft |
Coop and run columns are the bird count times 4 and times 10. Indoor minimum is the count times 1.5 and times 2 (Penn State laying hens 1.5 sq ft and large chickens 2 sq ft; Maryland prints that table; Utah lists 1.5 to 2.0 sq ft). Laying-hen run is the count times 8, the Penn State and Maryland laying-hen run line; their large-chicken run line is 10 sq ft, which matches the run column. Nests, 1 per 4-5, are the count divided by 5 and by 4, rounded up (Minnesota, Utah, and Maryland). Penn State nests are 2 for the first 4 hens, then 1 more per 4 additional hens, with a remainder rounded up. Feed per week is the count times about 3 lb for a 6-pound hen (Minnesota). That weekly column is not the 6-hen page's monthly bag line, which uses the calculator's quarter-pound daily rate (Alabama Extension and Kentucky Extension ASC-191). Example floors are side lengths that multiply back to the coop and run areas. Another pair of sides with the same product is the same floor. The nesting-box page and the roost page hold box size and perch length. Weekly cost is in the feed cost guide.
Worked examples
4 hens, and the 5 × 8 ft rectangle
Four times 4 sq ft is 16 sq ft, a 4 × 4 ft floor. That square is the planning floor, not the minimum. The minimum is 4 × 1.5 = 6 sq ft through 4 × 2 = 8 sq ft. Penn State feeder space is 3 in × 4 = 12 in, one foot of trough. The 40 sq ft run is 5 × 8 ft. That same 5 × 8 ft rectangle is the coop floor for 10 standard hens (10 × 4 = 40 sq ft). Same lumber, different job: outdoor space for 4, indoor space for 10. The 10-hen run is 10 × 10 ft.
On nests, 4 divided by 4 is 1 and 4 divided by 5 rounds up to 1, so the 4-to-5 rule is 1 box. Penn State still assigns 2 nests to the first 4 hens. Report both. Do not average them into a box count nobody published. Box size, when you cut them: Penn State says nests at least 12 × 12 in, Maryland says one 10 × 10 in box per 4 to 5 chickens, and Utah says 12-15 in high and wide and at least 12 in deep.
Minnesota says hens lay roughly 6 eggs per week, so 10 × 6 = 60 eggs a week if every hen hits that rate. That is a laying figure, not a space figure, and it assumes the 12-14 hours of light Minnesota says hens need.
15 hens, when one roost does not fit the wall
Fifteen times 4 is 60 sq ft, a 6 × 10 ft floor, and 15 × 10 is 150 sq ft of run, a 10 × 15 ft example. The indoor minimum is 22.5 to 30 sq ft. That smaller band is not the plan. eXtension says too little space leads to pecking and cannibalism.
Utah at 10 in is 150 in, which is 12 ft 6 in. The 10 ft wall of the 6 × 10 ft example is shorter than 12 ft 6 in, so that upper allowance does not fit on one wall. Split the bar. Penn State at 6 in is 90 in, which is 7 ft 6 in, and 7 ft 6 in does fit on that 10 ft wall. Penn State spaces roosts 1 ft apart. Utah spaces perch bars 14 in apart. Heights and the 2×2 bar are on the roost page. Do not shorten the inches to make one stick fit.
30 hens, feeders in more than one place
Thirty times 4 is 120 sq ft, a 10 × 12 ft floor. Thirty times 10 is 300 sq ft of run, a 15 × 20 ft example. Penn State feeder space is 3 × 30 = 90 in. Maryland is 2-3 in, so 60 to 90 in. Those inches are split across separate areas, not hung as one trough, because 30 is more than 25 birds. Nipples stay one system: 30 ÷ 6 = 5, and 30 ÷ 8 rounds up to 4, so plan 4 to 5 nipples. One five-gallon waterer still covers the flock, because Maryland goes up to 75 hens and 30 is under 75. Weekly feed is 90 lb, one 50-lb bag plus 40 lb, using Minnesota's about 3 lb for a 6-pound hen.
Nest counts at 30 are 6 to 8 on the 4-to-5 rule (30 ÷ 5 = 6; 30 ÷ 4 rounds up to 8) and 9 on the Penn State count (2 for the first 4, then 26 ÷ 4 rounds up to 7 more).
Penn State Extension says to bury run wire at least 12 in deep and toe it outward about 6 in. Maryland Extension says to use 1/2-inch hardware cloth over windows. Neither sentence is a flock-count step. Both apply to the run and the openings on the houses above.
What changes past 25 birds
The per-bird floor and run rates on these pages do not step up at 25. A 25-hen house is still 25 × 4 = 100 sq ft inside and 25 × 10 = 250 sq ft of run. A 30-hen house is still 30 × 4 and 30 × 10. A 50-hen house is still 50 × 4 and 50 × 10.
The sourced layout change is the feeder. Penn State Extension says that with more than 25 birds, put feeders in separate areas. Exactly 25 is not more than 25, so the sentence does not yet apply. Twenty is under the line as well: one trough, 20 × 3 = 60 in on the Penn State feeder line (40 to 60 in on Maryland's 2-3 in). Thirty and 50 are over the line, so the inches are split. Inches for a single flock are on the feeder space page.
At 50 the waterer still does not grow with the feed bags. Weekly feed is 50 × about 3 lb = 150 lb, which is 150 ÷ 50 = 3 bags of 50 lb. Maryland still covers 50 hens with one five-gallon waterer, because the cap is 75. Nipples move: 50 ÷ 8 rounds up to 7, and 50 ÷ 6 rounds up to 9, so plan 7 to 9 nipples. Roost length will not be one stick. Penn State at 6 in is 300 in (25 ft). Utah at 10 in is 500 in (41 ft 8 in). Space the bars 1 ft apart (Penn State) or 14 in apart (Utah).
Light on the 200 sq ft floor
Maryland says one 25-watt bulb lights 40 sq ft, so 200 ÷ 40 = 5 of those bulbs cover a 200 sq ft floor. The same source says one 40-watt bulb lights about 200 sq ft, so 1 bulb of that size matches the 50-hen coop. Penn State says one low-intensity bulb (40 watts or less) every 40 ft at ceiling height, and that a bird needs only 1 foot-candle for year-round production. A 10 × 20 ft example of the 200 sq ft floor is 20 ft on the long side, and 20 is less than 40, so one bulb meets that spacing on a house of this footprint.
Those bulb figures are tied to floor area, not to a head-count cutoff at 25. The hour requirement is for laying hens generally: Minnesota says hens need at least 12-14 hours of light a day to keep laying, and Maryland says 14 hours total light maintains egg production. Heat lamps are a different question. The winter heat-lamp guide is the longer page on winter heat.
If the climate does not allow year-round outdoor use, eXtension says the interior space requirement increases. The source does not publish how many extra square feet. Do not swap the table's coop column for a made-up winter floor.
Breed-size variation
Stay on the row that matches the bird. The laying-hen 1.5 sq ft line is for standard layers. Bantams are a different row. Large birds are a third feeder line, and large meaty breeds are a roost refusal.
| Bird | Floor | Roost | Feeder |
|---|---|---|---|
| Standard laying hen | Planning rate on this site: 4 sq ft inside and 10 sq ft of run. Indoor minimum 1.5 to 2 sq ft. Laying-hen run minimum 8 sq ft. | Utah 6 to 10 in. Penn State 6 in, 18-24 in above the floor, never more than 4 ft. Maryland at least 6 to 7 in. | Penn State at least 3 in. Maryland 2 to 3 in. |
| Bantam | Penn State and Maryland minimum: 1 sq ft inside and 4 sq ft of run. Ten bantams are 10 sq ft and 40 sq ft. These sources do not publish a larger bantam allowance. | Penn State: 4 in of perch, 12-18 in above the floor. Do not apply Utah's 6-10 in standard-chicken line. | Penn State: 1 linear inch per small bird. Ten bantams are 10 in. |
| Large bird | Penn State and Maryland: 2 sq ft indoors and 10 sq ft of run for large chickens. That 2 sq ft is the top of the indoor minimum column, not the 4 sq ft planning rate. | Penn State gives large meaty breeds no perches. Do not saw a bar for that row. | Penn State: 3 to 4 in, not the 3 in standard line. |
Ten bantams at the published minimum: indoor 10 × 1 = 10 sq ft (a 2 × 5 ft example) and run 10 × 4 = 40 sq ft (a 5 × 8 ft example). Roost is 10 × 4 in = 40 in, which is 3 ft 4 in, set 12-18 in off the floor. The sources do not print a separate bantam nest ratio, so the standard nest methods are the ones on the table: one per 4 to 5 hens is 2 to 3 boxes, and the Penn State count is 4 (2 for the first 4, plus 2 more for the next 6). Ten standard hens are not this row. Their planning floor is 40 sq ft indoors.
The calculator's bantam setting is 2 sq ft indoors and 8 sq ft of run. For 10 bantams that returns 20 sq ft and 80 sq ft. That is extra room above the 1 and 4 minimum. It is not a second published bantam rate. Building larger than 10 sq ft for 10 bantams is a choice you make without another bantam number to multiply.
Body weight does not create a second feed rate in these sources. Minnesota lists Rhode Island Red and Wyandotte hens at about 6.5 lb and Orpingtons at about 8 lb, and it publishes roughly 3 lb of feed a week for a 6-pound hen. It does not publish a different weekly amount for the heavier weights. Eight standard hens stay at 24 lb a week on that 6-pound rate.
Common mistakes
- Building the minimum and calling it the plan. For 3 hens the minimum is 4.5 to 6 sq ft and the planning floor is 12 sq ft. The birds sleep, eat, and lay inside the 12. eXtension ties too little space to pecking and cannibalism.
- Averaging the nest methods. At 3 hens the 4-to-5 rule is 1 box and Penn State is 2, because 3 hens sit inside the first group of 4. At 5 hens the 4-to-5 rule is 1 to 2 and Penn State is 3. Keep the published counts separate.
- Splitting feeders at exactly 25, or leaving them as one trough past 25. Penn State's line is more than 25 birds. Twenty-five is on the line and does not cross it. Thirty does.
- Using a standard roost for bantams. Standard bars on the Penn State page are 6 in and 18-24 in high. Bantam bars are 4 in and 12-18 in high. Utah's 6-10 in range is not the bantam line.
- Cutting roost inches so they fit one wall. At 15 hens, Utah's upper end is 12 ft 6 in and the example coop's long wall is 10 ft. Add a second bar at the published spacing. Do not drop the inches.
- Inventing a winter add-on. eXtension says interior space increases when birds cannot go outside all year. It does not say by how many square feet. The table's coop column stays count × 4.
- Scaling the 3 lb feed figure for a heavier breed. Minnesota names 6.5 lb and 8 lb hens and still gives the weekly figure for a 6-pound hen. There is no second multiplier on that page.
- Trusting a prefab "fits this many chickens" label. Divide the listed interior by 4 and compare it with the coop column. The 6-hen page and the best-coops guide apply that test to six-hen houses.
- Adding birds into the current floor on day one. USDA APHIS says to quarantine new birds for 30 days. The current row, the quarantine pen, and the combined flock are three different calculator runs on how to introduce new chickens.
- Counting a nest a broody hen will not leave. The box count on this table assumes the nests are available. A hen that stays on the nest is on the broody hen page.
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FAQ
How big should a chicken coop be by flock size?
For standard hens this site multiplies 4 sq ft of coop and 10 sq ft of run by the bird count. The 4 sits inside the eXtension 3-4 sq ft indoor range and the Minnesota Extension 3 to 5 sq ft range. The 10 is the outdoor figure from eXtension. The table covers 3, 4, 5, 6, 8, 10, 12, 15, 20, 25, 30, and 50 hens. The indoor 1.5 to 2 sq ft band is a minimum, not the plan.
What changes when a flock is larger than 25 birds?
Penn State says to put feeders in separate areas when there are more than 25 birds. A flock of exactly 25 is not more than 25, so the rule is not in force yet. It applies at 30 and at 50. These sources do not publish a higher per-bird floor or run rate at 25. eXtension says the interior space requirement increases if the climate does not allow year-round outdoor use, and it does not give a replacement number.
How much space do bantams need compared with standard hens?
Penn State and Maryland list bantam chickens at 1 sq ft inside and 4 sq ft of run, both as minimums. Ten bantams are 10 sq ft indoors and 40 sq ft of run. These sources do not publish a higher bantam allowance. The calculator uses 2 and 8, which is above that minimum. Bantam roosts on the Penn State page are 4 inches long and 12-18 inches high, not the standard 6 inches at 18-24 inches.
Why do the nest counts disagree?
Minnesota, Utah, and Maryland say one nest per 4 to 5 hens. Penn State assigns 2 nests to the first 4 hens, then 1 more per 4 additional hens. The table shows both. Do not average the two methods into a third number nobody published.
Compiled with AI assistance from the sources below. Spot an error? Email jpanasuk@gmail.com.
Sources
- eXtension Small and Backyard Poultry, "Space allowances in housing for small and backyard poultry flocks". https://poultry.extension.org/articles/getting-started-with-small-and-backyard-poultry/housing-for-small-and-backyard-poultry-flocks/space-allowances-in-housing-for-small-and-backyard-poultry-flocks/. Accessed Oct 2, 2026.
- University of Minnesota Extension, "Raising chickens for eggs" (reviewed 2025). https://extension.umn.edu/agriculture/animals-and-livestock/poultry/raising-chickens-for-eggs. Accessed Oct 2, 2026.
- Penn State Extension, "Small Scale Poultry Housing" (updated June 25, 2026). https://extension.psu.edu/small-scale-poultry-housing/. Accessed Oct 2, 2026.
- University of Maryland Extension, "Housing Requirements" (updated May 11, 2022; space table from Clauer, 2009). https://www.extension.umd.edu/resource/housing-requirements. Accessed Oct 2, 2026.
- Utah State University Extension, "Housing Backyard Chickens" (peer-reviewed fact sheet, 2008). https://extension.usu.edu/poultry/research/housing-backyard-chickens. Accessed Oct 2, 2026.
- Alabama Cooperative Extension, "Feeding the Laying Hen". https://www.aces.edu/blog/topics/farming/backyard-small-poultry-flock-management-series-feeding-the-laying-hen/. Accessed Oct 2, 2026.
- University of Kentucky Extension ASC-191, "How Much Will My Chickens Eat?". https://publications.mgcafe.uky.edu/files/ASC191.pdf. Accessed Oct 2, 2026.