I'm putting a Dark Cornish Rooster on 6 Cornish Cross roasting hens. Those grew up better than the Jumbo Cornish Cross with few problems. They take about 2 weeks longer to reach the same size as the Jumbos.I had a broody hen hatch a double yolker, it was her own egg. I knew it was a double yolker when she went broody, but decided to let her try it. She was brooding eight eggs and ended up with nine chicks. They were both cockerels and stuck together from the very first, they were almost identical in looks and temperament. Their mother was a broiler and the sire was a dark Cornish.