I was very concerned about our 4 hens and 1 roo - similiar forcast here - calling for 30 below tonight, plus wind. Our coop is small (about 4x4) and is not insulated. For the door there is just a piece of fabric covering the entrance (they are safe from predators, the coop is inside a covered chain link run). I have no heat lamp, just a regular 60 watt bulb on at 430 am for extra daylight and off when the sun pops up. I was really concerned about them (last night was fridgid as well) but now I feel less so. My littlest boy helped me add a thermometer to the coop, just next to the roost bar - checked it at noon and its 20 in there - only 5 outside! WOW! They are out and about in the covered run and seem perky and full of it as always. YAY - I am sooooo relieved and so much less worried - I plan to not change anything tonight and will be checking them at day break tomorrow....