Any egg that will hatch! I would have loved for my little silkie Serama eggs to have hatched under the mama, but they didn't.....this time! My little silkie Serama rooster is more than likely too tiny to fertilize any of my large hens. I do have a Bantam Ameraucana x silkie or Polish hen he could service, but she hasn't laid her first egg yet so I'm supposing she is too young still.