Build a simple chicken coop

Size the coop from the flock

Decide the flock size before drawing any lines, and use the backyard chickens guide to check that the number fits your rules, space and care capacity. Coop floor-area comparison: backyard planning and US production figures Context Source Figure Qualification Backyard planning RSPCA At least 1 m² per bird Where possible; plan to this higher figure for a small backyard flock. Backyard space constraint RSPCA No more than three birds per m² of coop Where 1 m² per bird is not achievable; account for bird size and available space. US floor-pen layers University of Maryland Extension Two square feet (about 0.2 m²) per adult bird Production minimum, not a backyard welfare target.

Work the numbers both ways. Four hens at 1 m² each need roughly 2 m × 2 m of coop floor area, plus a separate run. This example does not establish a sufficient run size; allow enough outdoor area for the flock and for resting wet, muddy or barren patches. Bantams need less; large dual-purpose breeds need more. If the site cannot hold the space the flock needs, reduce the flock rather than the space.

Choose the site before the frame

Position the coop where it stays dry and usable all year: morning sun and afternoon shade, ground that slopes away from the house, and shelter from the prevailing wind. Keep it close enough for a two-minute daily visit in winter, and where you can reach every part of it for cleaning, feeding and repairs without dragging equipment across the garden.

Site the feed and water so wild birds and rodents cannot reach them, and keep the coop away from places where manure, dust or smell will drift into windows, seating or neighbours' gardens. A coop that is pleasant to maintain gets maintained; one that is awkward to reach becomes a health problem.

Build a simple frame and shell

A plain box or A-frame is the right shape. Raise the floor or build on a solid, level base to keep birds off damp ground, and protect the base against digging. Use weatherproof cladding with a roof overhang that keeps rain off the walls. For a walk-in coop, make the main door large enough to enter and clean the whole interior. For a small coop or A-frame, provide access doors that let you reach every interior surface and remove bedding from outside. Build sequence: 1. Establish flock size, space and site layout. 2. Prepare the raised floor or solid, level base. 3. Assemble the frame and weatherproof shell, allowing for high ventilation. 4. Fit cleaning-access doors and bird entrances. 5. Protect openings with welded mesh, fit secure latches and protect the base. 6. Install roosts and nest boxes sized for the birds. 7. Complete the enclosed run and its cover. 8. With the coop empty, test cleaning access and every latch, and inspect for gaps.

Give the birds more than one entrance, sized so they pass through without crouching. The RSPCA notes that multiple entrances help avoid bullying and encourage birds to use the outdoor area. Line the floor with a dry substrate such as wood shavings or straw, which lets birds forage, rest and dust bathe. Follow the bedding checks and replacement routine in 'Bedding, cleaning and maintenance'.

Protect every opening against predators

Identify the local predators—foxes, rats, stoats, cats, dogs, birds of prey—and design the whole enclosure against them, not just the door. Use welded mesh or hardware cloth rather than ordinary chicken wire: the RSPCA is explicit that chicken wire will not always keep predators and rodents out, and welded mesh is the better alternative. Cover every ventilation opening, fit secure latches that resist animal interference, and anchor or bury the base to resist digging underneath.

For the run, the RSPCA recommends sturdy fencing at least 6 ft tall, sloping outwards to deter foxes from climbing over. Predator resistance depends on the whole enclosure and regular inspection. Include mesh, latches and the base in the daily checks below, and repair gaps the same day.

Fit roosts and nest boxes

Roosts should be 3–5 cm wide with rounded edges, at a height that suits the birds' size—around 40 cm is the backyard guidance used here—and long enough for every bird to roost at once, from 15 cm per chicken. The width and length figures follow the RSPCA guidance. For comparison, University of Maryland Extension guidance gives six inches of roost per bird, with roosts and nest boxes about 24 inches (61 cm) above the floor. That height is higher than 40 cm; these are different recommendations, not interchangeable building instructions. Choose dimensions that suit the birds. Keep roosts clear of the nest boxes: birds that roost in the nests dirty them, and the two jobs need separate facilities.

Following the RSPCA guidance, provide at least one nest box per five hens, with a minimum of two boxes for any group size, each box at least 30 × 30 × 30 cm. Boxes should be quiet, enclosed and draught-free, lined with clean, dry material such as straw or wood shavings. For comparison, University of Maryland Extension guidance gives one 10 × 10 inch box for every four or five hens, always with clean, dry nesting material. Ten inches is 25.4 cm, smaller than the 30 cm minimum stated here, so the box dimensions are not equivalent. Use the stated minimum and ensure the boxes suit the birds' size.

Ventilate without draughts

A coop needs air movement to carry away moisture and ammonia, but the air should move over the birds, not through them. Put ventilation high in the walls or under the roof, above the roost line, and protect it with welded mesh. Ventilation helps remove moisture and ammonia and keep bedding dry; regular cleaning and parasite control are still needed.

Check the balance in practice: on a cold, still day the interior should not feel stuffy, and on a windy day the birds should not be in a draught. If you must choose, ventilate—damp, stagnant air does more damage to a small flock than a well-sheltered cold one.

Add the run and outdoor area

The run is where the flock spends most of its time, so build it to the same standard as the coop: full enclosure with welded mesh, overhead cover for shade, weather and predators, and enough area that wet, muddy or barren patches can be sectioned off while the rest stays usable. Keep the grass short, as long strands can become trapped in a chicken's digestive system, and leave patches of dry soil where the birds can dust bathe and forage.

Shelter outdoor feed and water to keep them clean and dry and to avoid attracting rodents and wild birds. If the run sits on lawn, rotate the flock between sections so the ground recovers; a run that turns to bare mud in a wet season needs more area, a deeper substrate or a move.

Bedding, cleaning and maintenance

Daily checks: Inspect mesh, latches and the base, and repair gaps the same day. Spot-clean soiled bedding, keep the floor covered in dry wood shavings or straw, top up as needed and replace bedding when it soils or compacts. In winter, check that ventilation is not blocked by frost and that bedding stays dry; in summer, confirm shade and water are adequate.

Weekly structural checks: In addition to the daily security inspection, walk the whole structure: mesh, latches and base, roof and overhang, door hinges, nest boxes and roosts. Note repairs as you find them; repair security gaps the same day. Periodic cleaning: The RSPCA advises regular cleaning and disinfection to remove parasites. Schedule a full clean-out to suit your flock and climate, with the coop empty for the job. Write the daily, weekly and periodic routine down so a backup carer can run it.

Check the rules

In Great Britain, keepers of any flock size must register their birds with the Great Britain Poultry Register, run by the Animal and Plant Health Agency under DEFRA, a requirement that took effect in October 2024 in England and September 2024 in Scotland. Registration exists so disease alerts and guidance can reach you. The statutory welfare code for laying hens applies to owners and keepers whether they have one backyard hen or a commercial flock; additional requirements in the code apply to establishments with 350 or more laying hens.

Confirm any local rules on flock size, roosters, siting and disease reporting with the responsible authority before you build, and read the full backyard chicken care and planning before birds arrive. A coop is the housing half of the commitment; feed, water, health support, manure and backup care are the other half.

Sources and review basis

1. Keeping chickens as pets: how to care for backyard hens — RSPCA
2. Construction – Specific Requirements — University of Maryland Extension
3. Code of practice for the welfare of laying hens and pullets — GOV.UK
4. Small Scale Poultry Housing — Penn State Extension

Coop space (1 m² per bird, maximum three birds per m²), perch width and length, nest box size and numbers, multiple entrances, bedding, cleaning and disinfection, welded mesh over chicken wire, the 6 ft outward-sloping run fence, run features and the Great Britain Poultry Register follow the RSPCA backyard chicken guidance. Floor-pen space of two square feet per bird, six inches of roost per bird, 24-inch roost and nest height, and one 10 × 10 inch nest box per four or five hens follow the University of Maryland Extension small flock construction guidance. The welfare code's application to backyard keepers and its additional requirements for establishments with 350 or more laying hens follow the GOV.UK code of practice; general housing design principles follow Penn State Extension. Local rules, registration and welfare requirements differ by country and locality, so the responsible local authority controls where this guide is general.