When is it that you call something wrong with the flock? I get eggs weekly from a farmer to hatch ducklings and so far out of almost 100 I've gotten 2 deformities. One could be explained due to crested being in his flock, brain outside of skull with deformed beak. The other I just found today in an egg that died. 2 headed, 2 spined. When is it that you start to wonder about what could be happening genetically