We're adding a coop to the run for our ladies for the winter. Their nest box is an old bookcase which will go into the coop and we'll add a roost inside also. My question: is there anything wrong with leaving the floor dirt? We live in CA's central valley where it rarely rains, snows every 10 or so years, somewhat foggy in January and February. So do I have to add a floor? Oh, we have no weasels or raccoons in the city where we live. Thanks!