Right now while our chicks are only weeks old we have them in a dog cage in the garage. We pull the tray out every other day and hose it off. But we are getting ready to build our first coop this weekend, and was wondering. Is hay fine for in the bottom floor of the coop? And how often should we change it out? What do you do with it when you change out the hay. We are going to have a wood flooring in our coop. Should we just spread a thin layer of hay for them to walk on or does it need to be thick? Thanks