If they are cold I myself wouldn't let any more cold air in then necessary, unless the sun can shine in on them to help warm them up. I have laying hens, and keep like 20 together in the coops to help them stay warm, and i have a dome light with a 100 watt bulb hung safely secured high up for light to keep the hens laying. my roof is metal and has a small space air gap at the top on all sides to let air in and gases escape. We will be putting vents in later.My silkies, sizzles various ages are in another coop and range of 4 to 14 in seperate pens young ones have heat lamps and some have 100 watt bulbs so a total of two 250 watt heat lamp and two 100 watt dome lights. It stays pretty warm in there, lights are hung and secured high enough for safety from shavings etc. but so the silkies, sizzles can get under to get warm if needed. I have a space on each side at the top of the roof also metal about a foot long 2inch gap for air circulation. still have to insulate roofs as the metal condensates with the temps outside and the heat inside. I don't let my silkies or sizzles out. but I do let my layers out , if the wind chill isn't to bad and the area is plowed or shoveled they will fly over the deep snow, there is a tent garage they like to play in and of course the barn. If they are huddling alot and really cold a dome light with a 100 watt or 75 watt bulb may help them warm up , I have to run an extention cord out to my coops, deep bedding would help too. sorry so long winded hope this helps you. take care
Thank you Paulajon!! I appreciate your info! That's my thought too so I've kept the pop door closed the past 2 days. My coop is 8x12 (chicken area is about 8x8) with gable vents at both ends. My nesting boxes are about 18 inches up one wall. I've placed a cardboard box--on it's side--under the boxes to block wind from the popdoor. I've also layered this area with hay so they can huddled in that. I'm doing DLM but I think it's too dry to give off any real heat. Surprisingly my silkie & sizzles were the ones that loved to be out in the pen. I have a heat lamp w/dome. I also had a 100 watt bulb in the chicken area & in the storage area but DH changed them to twirly energy saving ones. And while I do love him, he is so tight he squeaks. His concern is how much the heat lamps & coop lights affect the electric bill. Do you see a big increase?