I shall follow this one with interest. My Black stars aka Black Sex Links habitually lay double yolked eggs. So it's inevitable that if I don't candle them first, that one or two are going to make it into the incubator that I'm testing out. But as a rule I wouldn't waste my time. A single chick has a hard enough time as it is. But twinning in my snakes seems fairly common yet they are still stuck inside ONE egg. Anyhow, I learned something new today.