For the best health and comfort of the chickens, chicken coops have certain requirements.
Most importantly, a coop needs to be predator-proof. All of your chicken-raising time and money is wasted if a fox, dog, raccoon, or coyote finds its way into the coop to kill your feathered friends. A sturdy structure that can prevent such an onslaught is necessary. A solid floor or wire buried in a dirt floor will keep burrowing and digging animals out.
A coop needs to protect the chickens from the elements. Rain, snow, wind, and sun can be harmful. A fully-enclosed living space is all they need. Depending on where you live you may want to consider heating the coop for cold winters, but chickens can actually handle very cold conditions as long as there are no chilly drafts in the coop.
That being said, a coop needs adequate ventilation to prevent chicken respiratory diseases from developing. Especially in hot months, ventilation is a requirement to keep the chickens from overheating or becoming dehydrated. A design to allow for cooling air in summer and reduced drafts in winter is ideal.
I built my coop in a vacant horse stall in the barn. The structure of the barn itself is a deterrent to many predators, but I built the coop to withstand any animal that finds its way into the barn. It can be cold in winter and a bit stifling in summer so I designed the coop with chicken wire on the upper third of the walls to provide as much ventilation as possible. In winter I can cover the wire with tarps to help retain some heat. This design also allows me ample opportunity to watch the chickens.
For mental and physical well-being, each chicken should have at least four square feet of space in the coop. This assumes that they'll have access to the outside on most days. If the coop is their only living space, you should allot at least 10 square feet per chicken.
My coop is four feet by seven feet, a total of 28 square feet. Since I also have a chicken run for outside exercise and stimulation (more on that in a future article) that space allows seven chickens to reside comfortably. I don't have that many now so I have room to grow my flock.
A coop should be designed for easy cleaning. A clean chicken environment is a healthy chicken environment. I covered my coop's plywood floor with a sheet of linoleum to help with cleanup. A wide door will allow the soiled bedding material to be shoveled out.
Chickens instinctively sleep in high locations. Coops should have high roosting spots to allow the chickens to sleep high. The roosts should be two inches wide with rounded edges; a simple tree branch will work. The roosts should be long enough to allow each chicken to have at least 10 inches side to side. One long roosting pole may be all you need. For many chickens, each additional roosting pole should be at least 10 inches from another.
My roost is a long 2x4 board with the small end up, three feet off the floor. I rounded and sanded the edges. I also added shorter 2x4s at intervals with the wide side up. In very cold weather, chickens should be able to roost while fully resting on their feet; this keeps their toes from freezing. By providing both slender and wide roosts my chickens can determine which one they want based on the temperature.
For hens, a coop needs nesting boxes. The boxes should be raised off the floor but need to be lower than the roosts; my nests are 12 inches off the floor. If the nesting boxes are higher than roosts the chickens may sleep in the nests, soiling them excessively. The nesting boxes should provide some darkness so the hens can lay in a nice, safe spot. Each nest may be used by as many as five chickens so a few nests will accommodate many birds.
My nesting boxes are built on the outside of the main coop area. This provides more living space for the chickens in the coop and provides the out-of-the-way, dark space for layers. This design makes collecting the eggs easy too because a hinged door allows egg collection without entering the coop.
Coops can be designed in many shapes and sizes. I've seen coops that are replicas of the owner's house. Pre-fab sheds work great. Using supplies you already have reduces cost; my coop cost less than $100 and most of that was on hardware like hinges, latches, and handles because I already had most of the building material. The finished coop can be painted, but chickens don't care what it looks like.
Many coops for purchase seem outrageously expensive to me. They're smaller, less sturdy, and not as efficient as one designed for a specific chicken owner. If you want chickens, consider their needs and think about building your own coop. There are many resources available to help.
For more info, take a look at:
backyardchickens.com
mypetchicken.com