I moved my five week old chicks out to a section of the coop a couple of days ago. The temps in NH have been pretty low at night-- mid 30s, but they have been fine. I have a 250 watt heat emitter( no light- just heat) hanging on their side of the coop and the temp is about 55 on the floor, but 65 on the roost. At night all the chicks have made it to the roost to sleep. It always amazes me how fast they learn to roost!