I have about 20 chicks right now. I'm going to be building a coop shortly. I need a min and max size idea for the coop. I'm on a tight budget, but I'm not going to crowd them either, just want to know what range I have to work with. Also need to have height factored in. Lastly, the roost, does it mater how far off the floor it is? Is higher better? Anything would be a help right now.