I can't decide if I should put in a heat lamp for these few days. 2 of my chickens have some frostbitten tips on their combs. Those are the chickens with the extra long, floppy combs though, so the other chickens are fine. But I'm worried about this cold getting into their coop. I'm pretty sure today I'm going to put a tarp up on the outside of the west wall, where the wind is coming from and there is a door to get their eggs. How can I tell if it's warm enough? And what about them coming out for a few minutes for food and water? I shoveled out their run and got 'em all out to eat and drink, but they went right back in. There isn't room in their coop for their food & water.