Hi I just hatched out about 15 duck eggs, they are pure pekin from my own little flock. Some of them have the crest on the top of their heads... did something happen? I did not know they would have it and none of my adults have it and i could not find it on the internet. There is only two or three of them and one has a BIG crest looking thing and the others are smaller. I did not know if this was suppose to happen or not.... any ideas?