Chickens do not have many natural defenses, and building a chicken coop is the best way to keep them safe from harm. The best chicken coops feature enclosed areas for nesting and roosting, a protected run for exercise, and a source of food and water. The most important element to think about when building a chicken coop is protecting your birds from predators; chicken predators can dig under, climb into, or fly over a coop.
Determining how many chickens are to be housed in the coop will help the builder figure out how large the coop should be. Full-sized chickens need about 4 square feet of space per bird; bantam breeds like silkies can get by with a little less space. Building a chicken coop that is too small for the number of birds it holds may result in overcrowded conditions and health issues.
Chicken coops that house laying hens need to have at least one nest box. The box doesn't have to be big, just large enough to hold full-sized hens. Laying hens will share a nest box; a ratio of one nest box per three or four hens is a good way to start. Nest boxes can be added into the coop design when building a chicken coop, or they can be added after the coop is complete.
Consider adding in a few sturdy roosts when building a chicken coop. Chickens naturally prefer to sleep and perch on a roost. Sturdy dowels, thin limber or even tree branches can be used as roosts and replaced as needed. Ideally, the finished coop should have enough roosting space so that all the chickens can perch off the ground at the same time.
Predation is one of the biggest problems encountered by chicken owners. Building a chicken coop that uses 1/4-inch hardware cloth instead of plain chicken wire is a good way to keep chickens secure. Installing inexpensive solar lights around the coop will help cut down predator activity at night. If the coop is in an area prone to foxes and other digging pests, burying chicken wire around the coop edges will help keep these predators at bay.
A frame of lumber topped with sturdy plywood is an ideal starting point for a first chicken coop. Once established, a coop can be expanded as needed, or moved around the yard to give the birds access to new grass. Even if chickens are allowed to free-range during the day, building a chicken coop with strong materials is the best way to keep them safe at night.