I have chicks that are 3 weeks old and I refused to use a heat lamp, too many horror stories, and didnt want to leave a light bulb plugged in while I slept im paranoid about fires! I have raised them day 1 without any heat lamp or light bulb, and they are doing fine. I am in NC, I keep them in our mudroom (room between garage and house) it is unheated in there. We did have nights at 1st that were upper 30s lower 40s and they did great. They were in a wooden house. The 1st week of having them I would put in a dog house style box that I would show them their way in at night. It was lined with a carpet like insulation and then lined with on of those foil thin heat emergancy blankets that warm up when you touch them. Only used it for the 1st week b/c after that it was hard to get them all in without others running out LOL. They are now in one of those black dog kennels and still doing great. They dont and never had huddled when they sleep.