I have three chickens that are 3½ months old and are doing very well outside. I live in Connecticut where daily temperatures are around 80 to 85 degrees and low temps in the mid 50's I also have three newer chicks that are 3 weeks old. They are still inside and are also doing well. My question is...How soon can the newer chicks join the others outside in the coop/run? Any special instructions on combining them?