Is it necessary to put a heat lamp in the coop when it gets below freezing--about 20*F ??? Could thier feet freeze?

Angela, I wouldnt think their feet would freeze at that temperature, as my chickens' dont and they shouldn't unless it below ) or around there, but they would be very cold and their combs and wattles could get frostbite, depending on what type of chicken you have and the comb. I would recommend a heat lamp because of that reason. Another thing is, have lots of insulation or whatever you use to put on the coop floor. Like have lots of straw, woodshavings or anything like that. Hope it helps, Cochinmun