Is there an age when Buff chickens become broody and do I have to wait until the eggs become larger before they are viable to hatch? . I have 7 BO's, 2 roo BO's,3 mixed roo's, one one black australorpe hen. They all get along. I wanted to start leaving the eggs for a hen to get broody but not sure when to do this as the eggs are still small. They started laying at 5 months+3 weeks old beginning of march. They are now about 6+ months. I would like the BO's to hatch their babies as I chose this breed due to being told they are great brooders.