If you need a coop there are two obvious ways to go: buy one or build one. I personally built one because my dad is in construction and had the tools and he couldnt justify paying for one. I am very pleased with how ours turned out and i think that the personal satisfaction of it is well worth the work... #1: Ventilation: ventilation is a key factor in designing you coop, if you have poor ventilation it is easier for airborne diseases and the like to stay and muster in your coop thus making it easier to inhale and get sick. It is also important for keeping your coop cool in the summer. (i put boards over the holes at night in the winter) So remember to implement a sufficient system where you will get optimal air movement and keep you and your chickens breathing happy. #2: Functionality: You need to make sure it serves it's proper purpose or what's the point??? A few things to remember to put in are: a roost(s), accounting for how many you chickens you have AND if you plan on adding any more in the future; a feeding station, i am currently using a (poorly designed) box that just sits on the floor where they can just walk and poop in it. i plan on getting a new feeder tho because its annoying wasting food from them pooing in it, so don't make the same mistake i did, a few suggestions would be a trough or a bucket feeder, etc.; a water , a place (preferably off the ground) to hang a water. i have several waters out and around the coop but a main central one hanging in the coop by the feeder; Nesting boxes, you need to have an adequate ratio of hens to nesting boxes. i have 3 nesting boxes and 8 hens and for some reason they all use the same one, i dont know why??? so remember that you don't actually need one box per hen. walking/casual room, if your chickens are going to stay in the coop full time, make it a priority to have walking space for them to mill around in and not be too crowded. A walk in door, this is needed for when you need in to clean, refill feed/water etc; a poop board, is placed under the roost and popularly filled with sweet PDZ to maintain a freshness to the coop, make cleaning a breeze (just sift and toss) and take away pretty much all odor. (i dont currently have a poop board but am working on implementing one); and lastly a Window(s), this is a nice option of course so you can see your chickens and let light in for them without letting in the elements... So thats all i can think of for now and if i left out any thing or you have any suggestions please let me know #3: Capacity: Consider how many chickens you will have and how many it will be able to hold, don't forget to account for if you want to expand your flock in the future, because you don't want to have to build a whole new bigger coop! #4: Overall Size: make sure its not to big if your in an urban environment because something to big could become an eyesore or petpeeve to neighbors and we wouldnt want that! #5: Aesthetics: Of course... go ahead, have some fun with it and make it look perdy for the birdies! I hope that this has been of some assistance and if anybody is building a coop and this was of any assistance please post pics! I wish you all the best of luck!