Chicken coop guide: sizing for 10 hens, materials, and keeping rats out

A coop is the one piece of poultry kit you cannot easily fix after the fact, and 2 numbers decide whether it works: square feet per bird and the mesh size that keeps rats out. Sellers list a coop as holding 8, 10, or 12 birds, but those counts assume the chickens never go inside in bad weather – the honest way to size chicken coops for 10 chickens is by floor area. This guide does that math, then covers what to build the coop from (wood, plastic, or metal), how to ventilate and lay out nests and roosts, and how to rat- and predator-proof the run so the flock survives its first fox or rat invasion. It is the housing companion to the flock-care basics in our guide to keeping backyard chickens; for the birds themselves, see raising chickens for eggs.

Sizing a coop for 10 hens

Space is the first thing to get right, because a crowded coop drives feather-picking, disease, and stress that no amount of management fixes later. The rule is simple – size by the square foot per bird, indoors and out – and a 10-hen flock makes the arithmetic easy.

For laying hens, poultry extension guidance recommends “a minimum of 3-4 square feet/hen indoor” and “10 square feet/hen outdoor.” Run the numbers for 10 birds and the coop lands at about 30 to 40 square feet of floor – roughly a 6 by 6 ft house – with a run of about 100 square feet, say 10 by 10 ft. That outdoor figure matters most: chickens spend their days foraging, and a tight run is where boredom-driven pecking starts. If the birds will free-range, you can shave the run, but the coop floor is the hard minimum for the hours they are shut in.

Wood, plastic, or metal: what to build it from

With the size set, the next choice is material, and it is a real trade between cost and upkeep. The 3 options a backyard keeper meets are wood, plastic, and powder-coated metal, and they differ most on cleaning and parasites.

Wood is the traditional and cheapest build, warm and easy to modify, but it is porous – droppings soak in, and red mites “work their way into every tiny crevice,” which makes an infestation “almost impossible to eliminate” without treating the wood after every clean. Plastic flips that: a molded coop can be pressure-washed and disinfected in minutes, mites “can’t work their way into the plastic itself,” and some recycled-plastic models carry a 25-year guarantee with no rot or repainting. The catch is a higher sticker price and less insulation. Metal coops – usually powder-coated steel – are the most durable and predator-resistant, but conduct heat and cold and are the priciest of the 3.

Ventilation, roosts, and nesting boxes

Those material choices wrap around an interior that has to do 3 jobs: breathe, give the birds a place to perch, and give them somewhere private to lay. Get the ventilation, roosts, and nests right and the coop runs itself.

Ventilation: the winter killer is damp, not cold

The thing that harms a winter flock is not cold – it is the moist, ammonia-laden air from droppings and breath, which causes frostbite and respiratory disease. The fix is high ventilation: place vents well above the roost so warm, humid air rises and escapes while the birds stay out of the draft, a rule of thumb of about 1 square foot of vent per 10 square feet of floor. Keep those upper vents open year-round, under a cover so snow stays out.

Roosts and nest boxes

Chickens sleep on a roost, not the floor. Provide 6 inches of roost per bird, set the bar 18 to 24 inches above the floor and about 1 foot out from the wall – so 10 hens want roughly 60 inches of perch. For laying, give a 12 by 12 inch nest box for every 4 to 5 hens; PSU Extension’s rule is “two nests for the first four hens” and one more per four after, which puts a 10-hen flock at 2 to 3 boxes. Add 3 inches of feeder space per bird and 1 water nipple per 6 to 8 birds, and the fittings are complete.

Keeping rats and predators out

A coop that houses hens also advertises a free meal – of eggs, feed, and the birds themselves – to rats, raccoons, foxes, and weasels. Rodent- and predator-proofing is built into the structure, and it comes down to the right mesh, a dig barrier, and clean feed.

The single most important choice is the mesh. Chicken wire keeps chickens in but does not keep predators out – raccoons tear through it and rats and weasels squeeze through the gaps. Enclose the run in half-inch hardware cloth instead, which excludes rats, weasels, and snakes. To stop diggers, “bury hardware cloth 2 feet down, and/or place a skirt of hardware cloth 2 feet out” along the ground. Elevate the coop off the ground so rats cannot nest beneath a rotting floor, and screen every window and vent with the same half-inch cloth.

Cut off the food

Rats come for feed first. Store it in tightly covered metal barrels, never an open bag a rat can chew, and feed the birds inside the secured run rather than leaving a feeder out overnight. A coop that is sealed in half-inch cloth and holds no loose feed gives rodents nothing to come for – far more effective than any poison, which also risks the flock. Pastured birds moved daily, as in pastured poultry on a chicken tractor, sidestep some rodent pressure simply by never sitting in one spot.

Building it to last

A good coop is 4 decisions made in order. Size it by the square foot – 3 to 4 indoors and 10 in the run per hen, so a 10-hen flock gets about a 30 to 40 sq ft coop and a 100 sq ft run. Choose a material – wood for cost, plastic for mite-proof cleaning, metal for toughness. Fit the inside for the birds: high ventilation above the roost, 6 inches of perch each, and a 12-inch nest box per 4 to 5 hens. Then seal it in half-inch hardware cloth with a buried skirt and keep the feed in metal – the difference between a flock that thrives and one a rat or fox empties in a night. Build those 4 right and the coop is the last poultry problem you will have to solve. With the birds housed, the day-to-day of the flock is covered in our backyard chickens guide.