Well, the incubator was really inconsistent (eggs got up to 106 F), so only 45% of the eggs hatched. To see what happens, I dissect the eggs to see how far developed the embryos get.
Imagine my surprise when I opened up one of the eggs, and found two ducklings attached to one yolk! Most people have heard of double yolked eggs, and less then 0.02% of eggs have this. Of these eggs, 1 out of 200 can hatch.
These guys were very advanced in development, as they usually die in the first week. They compete for space, oxygen, and resources.