How Much Space You Need for 20 Chickens
A coop for 20 chickens needs at least 40 square feet of interior floor space — that is 2 square feet per bird minimum, the standard that prevents disease and stress. For a flock of 20, most builders go to 60 or 80 square feet to give room for feeders, waterers, and movement without crowding. A 10-by-6-foot coop or an 8-by-8-foot coop both work; the shape matters less than the total area.
Outside the coop, chickens need a run — an enclosed yard where they can scratch, dust-bathe, and forage without predators reaching them. Plan for 4 square feet per bird in the run, so 80 square feet minimum for 20 birds. A 10-by-8-foot run is typical. If you cannot build a run that large, rotate the flock between two smaller runs to avoid bare ground and disease buildup.
Roosts take up vertical space, not floor space. Chickens sleep on bars or branches 2 to 3 feet off the ground. For 20 birds, you need about 8 to 10 linear feet of roost — a single 10-foot bar, or two 5-foot bars. Mount them 12 inches apart so droppings fall between them, not on birds below.
Key Takeaways
- A 20-bird coop needs 40 to 80 square feet of interior space, with 10-by-6 or 8-by-8 feet being common sizes.
- Build the coop with 2 to 3 feet of headroom, hardware cloth (not chicken wire) on all sides, and a predator-proof door that closes every night.
- Nesting boxes — one for every three birds — should sit 18 inches off the ground and be 12 by 12 inches inside.
- Roosts need 8 to 10 linear feet of bar space, mounted 12 inches apart so droppings fall between them.
- A run attached to the coop should be at least 80 square feet, with hardware cloth buried 6 inches underground to stop burrowing predators.
Choosing the Right Location and Foundation
Place the coop on high ground where water drains away after rain. Wet bedding breeds disease and parasites. If your yard slopes, build on the high side. Avoid low spots that collect runoff or stay muddy.
The coop needs 6 to 8 hours of sunlight daily but should have shade in the afternoon, especially in hot climates. A spot that gets morning sun and afternoon shade from a tree or building works well. Full shade all day leads to damp bedding and vitamin D deficiency; full sun all day stresses birds in summer.
For the foundation, pour a concrete slab or lay concrete blocks under the perimeter to stop predators from digging underneath. If you use a wooden frame, set it on concrete blocks rather than directly on soil — wood rots, and soil contact invites termites and burrowing animals. Leave a 6-inch gap under the coop so you can inspect for predators and clean out debris.
Building the Walls, Roof, and Ventilation
Use hardware cloth, not chicken wire. Chicken wire keeps chickens in but does not stop raccoons, foxes, or weasels — they tear through it. Hardware cloth is a wire mesh with half-inch or quarter-inch openings. Cover all walls and the roof with it, or use it on the lower 3 feet of walls and solid wood on top. Staple it every 4 inches so predators cannot peel it back.
The coop frame can be 2-by-4 lumber or 2-by-2s for smaller builds. Make the walls at least 2 feet tall so you can stand inside to clean and collect eggs. Most builders go to 6 or 7 feet at the peak so the roof sheds rain and snow. A sloped roof is better than flat — water pools on flat roofs and rots the wood.
Ventilation prevents ammonia buildup from droppings and keeps the coop dry. Cut vents near the roof on opposite sides of the coop — high vents let hot air escape in summer. Cover vents with hardware cloth so predators cannot enter. In winter, vents stay open; do not seal the coop tight or moisture will condense on birds and bedding.
Nesting Boxes and Roosting Bars
Chickens lay eggs in nesting boxes — dark, enclosed spaces that feel safe. For 20 birds, build 6 to 7 boxes (one for every three birds). Each box should be 12 by 12 inches inside and 12 inches tall. Mount them 18 inches off the ground so hens can hop in but predators have a harder time reaching eggs. Slant the roof slightly forward so eggs do not roll out and birds do not roost on top.
Line each box with 4 inches of bedding — wood shavings, straw, or shredded paper. Hens will add more as they nest. Check boxes daily for eggs and remove wet or soiled bedding twice a week.
Roosting bars are where chickens sleep. Use 2-by-2 lumber or branches 2 to 3 inches in diameter. Mount them 2 to 3 feet off the ground, 12 inches apart. For 20 birds, install 8 to 10 linear feet of roost — a single 10-foot bar works, or two 5-foot bars. Slope the bar slightly so droppings slide off. Place a droppings board or deep bedding underneath to catch waste and make cleaning easier.
Feeders, Waterers, and Interior Layout
Chickens eat about 0.25 pounds of feed per bird per day, so 20 birds eat 5 pounds daily. Use a hanging feeder or trough feeder that holds at least 25 pounds of feed — this lets you fill it less often and keeps feed dry. Hang feeders at shoulder height so birds do not scratch bedding into them.
Water is critical. A 5-gallon waterer serves about 10 birds for one day in cool weather, less in heat. For 20 birds, use two 5-gallon waterers or one larger system. Raise waterers on a stand so chickens do not kick bedding into them. In winter, use heated waterers or check twice daily to break ice.
Inside the coop, arrange boxes on one wall, roosts on another, and feeders and waterers in a corner away from the roosts — chickens will not eat or drink near where they sleep. Leave open floor space for dust-bathing and movement. Spread 4 to 6 inches of bedding on the floor — wood shavings, straw, or a mix. Change bedding weekly or when it gets wet or packed down.
Building and Securing the Run
The run is an enclosed yard attached to the coop where chickens can be outside safely. For 20 birds, build a run at least 10 by 8 feet. Use 2-by-2 lumber for the frame and cover all sides and the top with hardware cloth. The top is essential — hawks and owls hunt from above.
Bury hardware cloth 6 inches underground around the perimeter or lay it flat on the ground and cover it with soil. This stops raccoons, foxes, and groundhogs from digging in. If you cannot bury cloth, lay it flat in a 12-inch band around the outside of the run and stake it down.
Build a door between the coop and run that you can open in the morning and close at night. Use a sliding door or a hinged door with a strong latch — not a straightforward hook that a raccoon can open. Many builders add an automatic door opener that closes at dusk and opens at dawn, which removes the daily chore and protects birds if you sleep late or travel.
Materials and Cost Overview
| Component | What You Need | Notes |
|---|---|---|
| Lumber (frame) | 2-by-4s and 2-by-2s, roughly 200 linear feet | Pressure-treated lasts longer but costs more; untreated is cheaper and safer for birds |
| Hardware cloth | 500 to 600 square feet | Half-inch mesh is standard; quarter-inch stops smaller predators but costs more |
| Roofing | Corrugated metal or shingles for 100+ square feet | Metal sheds water faster; shingles last longer |
| Nesting boxes | 6 to 7 boxes, 12 by 12 inches | Build from scrap wood or buy prefab boxes |
| Roosts | 8 to 10 linear feet of 2-by-2 or branches | Branches are free if you have trees; 2-by-2s are uniform and easier to clean |
| Bedding | 8 to 10 bags of wood shavings initially | Budget for weekly changes; shavings cost $5 to $8 per bag |
| Feeders and waterers | 2 feeders, 2 waterers | Hanging feeders run $20 to $40; waterers $15 to $30 |
Total material cost for a 20-bird coop and run typically ranges from $800 to $1,500, depending on whether you use new or reclaimed lumber and how much you build yourself versus buying prefab sections. Labor is the biggest variable — a professional builder charges $2,000 to $4,000 or more.
The largest ongoing expense is bedding. Wood shavings cost $5 to $8 per bag, and you will change bedding weekly or every two weeks depending on the season. Feed costs about $15 to $25 per month for 20 birds, depending on the brand and whether you supplement with kitchen scraps. Water is minimal unless you heat it in winter.
Predator-Proofing and Maintenance
Predators kill more backyard chickens than disease does. Raccoons, foxes, weasels, hawks, and owls all hunt chickens. The coop must be locked every night — even one night left open can wipe out the flock. Use a sliding bolt or padlock on the door, not a hook or latch a predator can manipulate.
Walk the perimeter of the coop and run monthly, looking for gaps, loose hardware cloth, or holes. Predators are persistent — a weasel can squeeze through a hole the size of a quarter. Patch any damage when ready with hardware cloth and staples.
Clean the coop weekly. Remove wet bedding, droppings, and old food. Wet bedding breeds parasites and respiratory disease. In winter, add fresh bedding on top of old bedding rather than removing it — the decomposing layer generates heat. In spring, do a full cleanout and disinfect with a 10 percent bleach solution.
Check the roof and walls after storms. Wind, snow, and falling branches damage wood and hardware cloth. Repair damage the same day so predators do not find an opening.
Frequently Asked Questions
Can I use chicken wire instead of hardware cloth?
Chicken wire keeps chickens in but does not stop predators. Raccoons, foxes, and weasels tear through it easily. Use hardware cloth on all exterior surfaces, especially the lower 3 feet where predators dig and climb. Chicken wire is cheaper but will cost you birds.
Do I need a run if I have a large yard?
Free-ranging chickens are vulnerable to hawks, foxes, and neighbors' dogs. A run gives them outdoor space and protection. If you cannot build a run, keep birds in the coop during the day and let them out only when you are home to watch. Many flocks are lost to daytime predators.
How often do I need to change bedding?
Change bedding when it gets wet or packed down, usually once a week in warm months and every two weeks in winter when the coop is drier. Wet bedding breeds disease and parasites. In cold weather, add fresh bedding on top of old bedding rather than removing it — the decomposing layer keeps the coop warmer.
What temperature is too cold for chickens?
Most chicken breeds tolerate temperatures below freezing, but water freezes and birds huddle together, which spreads disease. In winter, use heated waterers, may support good ventilation to prevent moisture buildup, and provide extra bedding for insulation. Extreme cold below minus 10 degrees Fahrenheit stresses even cold-hardy breeds.
Can I build a mobile coop instead of a fixed one?
Mobile coops work for small flocks (6 to 10 birds) but are heavy and awkward for 20 birds. A fixed coop with a run is easier to manage, cleaner, and more predator-proof. If you want to move birds between pastures, build a fixed coop and rotate the run to fresh ground instead.