I have 15 4 week old chicks...is it to soon to let them stay outside in the coop and run? Its all wire, nothing can get in..but just a dog house for them to get away from any foul weather. I can set up a heat lamp...but they haven't been under one in the garage. They have been out there in the day, and seem to love it...Hate to bring them in! Also have an 8 week old out there with them. And at what age do they start eating scratch instead of the baby grit? Thanks!