I have raised chicks in a brooder and I have let broody hens raise chicks. My question has to do with heat requirements. I have watched chicks raised by a Mama Hen run around for hours in cool temps without getting under Mama for warmth and I have seen chicks sleep out from under Mama when the night-time temps are in the low 70's. And these are very young chicks that haven't feathered out yet. But the chicks I raised in a brooder seem to need high temps or they cheep and huddle up. It seems to me that the brooder raised chicks need more heat. Can anyone tell me why?