it is starting to get cool in the day and cold down to mid 30's at night. My coop is cement block about 6 ft up Has 6 windows and 2 doors. How warm do i need to keep it? Do i need heat lamps and such everyngiht? I use straw and junk hay for bedding. FYI The coop has a a 2nd floor but ther isnt anything in it but junk. The chickens cant get up there.