I have Barred Rocks, Buff Orpingtons, Rhode Island Reds, and some mixed breeds. These guys have had access to the run up until about a week ago when we got our first snowfall. They refuse to enter the run. One chicken hopped out of the coup, but as soon as he hit the snow, he high tailed it back into the coup and won't go out. I have a heat light in the coup, and for the last week have decided to leave the run door shut to conserve the warmth in the coup. Just curious what temps these guys can handle? It's been -8 here at it's worst this week and about 15 degrees at it's warmest. It does get colder than that the further into winter we are. The chickens are almost 6 months old, none of them laying yet. The heat light is also in there to prevent the water container from freezing.