First of all I would like to say thank you to all of you who ask and answer questions on here...it has helped me a great deal. I will be receiving my first chicks in mid-april and would like to be prepared for them. I will be starting out with about 20 chicks. Anyways, we recently moved to an area with a very large amount of clay in the soil so it retains water very well, and being that it is in Wisconsin we have very cold winters. (sometimes, lol!) I know that if we used concrete for the floor it would crack in no time, so I was thinking that cement blocks or patio blocks would work since they would be able to shift with the ground if I built a new coop. On the other hand we could always use the older pole shed/barn. There is a room with some concrete on the floor where someone had made living quarters at one point. It is insulated and has paneling over the insulation. There would be plenty of room for the chickens and lots of room to expand if the need ever arose plus room for storage. There is a window on the south side as well as a door with a window. What will be the best for the chicks as they grow?