We have 6 chickens and live in WNY (aka cold and snow) we have been busy making modifications to the coop and run to accomodate the cold weather. Our last change was to put in a red ligt vs white in the heating lamp. Last night three of the chickens did not go into roost and it was down in the teens. In addition, our modifications now have the run covered either with a snowbank or tarp on three of the sides. Any ideas on why they didn't go in?