Hi! We have ten baby chicks that we have built a separate pen in our insulated chicken house so they are separate from the old ladies. They are two months old and getting quite big. We still have the brooder lamp on them but the old ladies are telling us it is too hot in there for them. How long do I need to keep the brooder lamp on the babies? I live in MN and Mother Nature has had a bulls-eye on us for the longest winter ever. But it sounds like we could be taking a turn and heading to the 50's and 60's. Also our chicken house is insulated. thanks!