My chickens haven't had a heat lamp since they left the brooder and moved to the chicken coop. They are now about 16 weeks old and i live in cold cold Northern Michigan. Of course its not cold here yet but its going to be soon. So i am confused as wether or not to put a heat lamp in their chicken coop for winter or not. And if so is it going to mess up their routines since they haven't had a heat lamp in the coop since they were 8 weeks old? HELP!