I brooded my chicks this year with a heating pad. They were fully integrated by 4 weeks. That being said, they had more space, and I let my flock free range until a pair of hawks discovered my buffet. So, I've spent the last few weeks shuffling the youngsters in and out of a tractor depending on the hawk issue. The youngsters are 2 months old now, and spending 24/7 with the older flock. You'll just have to try it and see how it works.