If you have basic building skills you can build your own coop with better quality and way cheaper then anything you can buy that is of any decent quality. All of the little pre fab coops at farm stores claim to hold about 15 hens and are poorly made. They could only hold a few at most. As others have said plan on 4 sq. foot per bird of coop space. If you are going to have feeders, inside nest boxes etc. then you will need a little more space. I build mine 6x8 with 7 foot walls (8 foot peak). I had the windows and tin for the roof donated but the lumber (treated from the floor down, standard pine from floor up) for just under $300.00. A similar sized coop from one of those road side barn builders would sell for a couple thousand. If you don't have the building skills a pre built shed from Lowes, Menards, Home Depot are usually the next best bet for quality/price. Some easy mods and it is ready for hens.