Your chicks are on order and the brooder tub is all set up and ready for them. Now you just need a place to put them when they're ready to move outdoors. You need a chicken coop, a henhouse, a chicken tractor -- but which one? And how big should it be? Can you convert an old shed to a chicken coop?
The type of coop you choose depends on whether the chickens will live full-time in it, have access to an outside run or larger portions of pasture, or whether it will be a movable coop that can be relocated frequently for fresh ground.
Decide on Square Footage
You will then need to determine the amount of space you need for the number of chickens you have. One especially important consideration is how many chickens you plan to keep on an ongoing basis. You might want to build on the large side, allowing for new baby chicks either bred or bought, or for future flock expansion.
If your birds will have access to an outdoor run, you'll want to allow for a minimum of 2-3 square feet per bird inside the coop, and aim for about 4 square feet per bird in the run. The higher you can go, the better, though. If your birds will be cooped all winter (chickens don't like to go out onto snowy surfaces), allow for 5-10 square feet per chicken. For birds that will be completely confined in a chicken tractor without an outdoor pen, give a minimum of 5 square feet per bird. These are just general guidelines. The bigger the chicken, the more space it needs - so meat birds in general require more space than laying hens, and full-grown pullets need more space than baby chicks. Most annoying chicken problems like pecking and aggressiveness can be cured with more space, so plan for as generously-sized a coop as you can fit or afford.
Consider Which Features You Need
Chicken coops vary from a very simple floorless wooden box with chicken wire surrounding it and a piece of roofing on it, to some digs that are more spacious than some human habitats! There are so many options, and it can seem daunting to choose a design.
If you are an urban or suburban homesteader, you may need to consider aesthetics and security of the flock (from escaping into neighbors' gardens) more highly than those in a rural setting. There are many plans for chicken coops that look attractive. Sometimes they have a whimsical design aesthetic.
If you have laying hens, they will need one nest box or one square foot of community nesting space per 4-5 hens. Most laying chickens like to roost. A good rule of thumb is 6-10 inches of roosting space per bird. Roosts should be at least 2 feet off the ground, as should nest boxes. Nest boxes should be about 1 foot square, or "community" nests should have at least one 9 by 12 inch opening every 20 square feet of nest space.
Roosts can be as simple as a ladder fastened to the wall at an angle, or twigs attached to the walls of the coop. Milk crates or plastic tubs lined with shavings or straw make fine nest boxes; just attach them to a shelf or to the wall directly.
Coops and tractors must have ventilation, so that gases from birds' respiration and poop don't build up inside. Chickens love shade, so a coop and run should include shady spots. Areas where hens can dust bathe is a nice addition. This can be as simple as a box filled with dirt or sand if there isn't a spot on the floor of the coop. Hens with access to outdoors will find places for their dust baths. In winter, my hens just pick a clean spot somewhere in the coop, usually a corner.
Decide Whether to Reuse, Build or Buy
Do you have a doghouse or shed that can be repurposed into a coop? Don't build a new structure if you don't have to. If you're not a builder, you can search craigslist or other classifieds for potential coop buildings small enough to be moved to your property. A new coat of paint, some ventilation put in (cut holes and cover with chicken wire or install windows), and some nest boxes and roosts inside, and you're in business. One thing to consider is the floor system - a wood floor can rot if you use the deep litter method, so expect more frequent cleanouts. A building without a floor can be put on the earth for the deep litter method, or on a concrete slab.
If you can't find an already-built structure to reuse, consider whether you want to build the coop yourself or buy one premade. For urban homesteaders and hobby farmers with small flocks and aesthetic considerations, buying a premade coop might make sense. For small farmers with a few dozen hens, building a coop is probably a better economic choice.
Find Plans and Ideas
You now know: what size coop you need, what basic type of coop or tractor you need, whether you need roosts and/or nest boxes, and whether you're renovating, building or buying your chicken coop. Here are some resources to look at for inspiration, plans, and premade coops.