I have 6 hen ducks, 5 of them were hatched in early May, the 6th is one of the "Moms" of these young hens. They are crossbred from a Rouen drake. The young hens started laying eggs about a month ago. Some of the eggs are HUGE. Not only are they huge, but these big eggs nearly always have a double yolk, one even had a triple yolk!! I'm not sure which female(s) are laying the big eggs since they are never "in process" when I let them out in the morning. All I can say is I know why the girls "waddle" now. None of the "moms" ever layed eggs this large and I think only one egg from the moms ever had a double yolk. Is the double yolk trait hereditary? Is it unusual? Do double yolk eggs hatch well or do they even hatch at all?