I bought a little 4 ft x 2 ft coop at first because I only had 4 chickens then I wanted more. Everything I found was too small then my husband got all this material for free so we put our heads together to build a coop.Building bigger is often suggested on the welcome thread. Sadly, many do not believe the advice!
I still have the little coop and use it for chicks until they're ready to go out with the big flock.