Mine just started laying Oct 23 and laid well all winter. They stayed out in the plasticked run all day except for the 4 or 5 coldest days. My coop is insulated and I have a heat lamp set to come on at 20 degrees and stay on til 30 degrees but even with the lamp it sometimes got down to 8 degrees in the coop, just depending on how cold it was at night. I put straw down in the run and that is much warmer than the sand underneath. I do highly recommend putting plastic around the run, leaving ventilation at the top. They can't take the wind.