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. The RSPCA advises at least 1 m² of housing per bird where possible; where that is not achievable, stock no more than three birds per m² of coop. US extension guidance for layers on a floor pen goes as low as two square feet (about 0.2 m²) per adult bird, but that is a production minimum, not a welfare target—plan to the higher figure for a small backyard flock.

Work the numbers both ways. Four hens at 1 m² each need roughly a 2 m × 2 m coop, plus a run of similar or greater area. 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 so the birds stay off damp ground and diggers cannot work underneath. Use weatherproof cladding with a roof overhang that keeps rain off the walls, and make the main door large enough for you to stand in and clean the whole interior.

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 dustbath, and top it up or replace it as it soiles.

Predator-proof every opening

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 latches that a determined animal cannot work, and anchor or bury the base so nothing can dig under.

For the run, the RSPCA recommends sturdy fencing at least 6 ft tall, sloping outwards to stop foxes climbing over. Inspect the mesh, latches and base as part of the daily routine, and repair gaps the same day. A predator-proof coop is not a single strong door; it is the absence of any opening an animal can reach.

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 lets chickens feel safe and reduces pecking—and long enough for every bird to roost at once, from 15 cm per chicken. US extension guidance gives six inches of roost per bird, with roosts and nest boxes about 24 inches above the floor. Keep roosts clear of the nest boxes: birds that roost in the nests dirty them, and the two jobs need separate facilities.

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. US extension guidance is similar: one 10 × 10 inch box for every four or five hens, always with clean, dry nesting material.

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 cover it with mesh so it cannot become an entry point. A well-ventilated coop stays dry inside, which is the single biggest defence against parasites, respiratory problems and rotten bedding.

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 dustbath 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

Keep the floor covered in dry wood shavings or straw, topping up as needed and replacing it when it soils or compacts. The RSPCA advises that coops be cleaned and disinfected regularly to remove parasites, so build a routine: daily spot-cleaning of soiled bedding and a full clean-out on a schedule that suits your flock and climate, with the coop empty for the job.

Walk the structure weekly: mesh and latches, roof and overhang, door hinges, nest boxes and roosts. Note repairs as you find them rather than letting a small gap become a fox entry. In winter, check that ventilation is not blocked by frost and that bedding stays dry; in summer, confirm shade and water are adequate. Write the 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 chickens assessment 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.