Are you serious?? I was just making a joke about that! Does that really happen? I swear, I picked up every bird to make sure I knew the sex before I culled the rest so I would have a breeding trio. Then about a month or so ago, this one sprouts drake feathers and is whispering away like a drake. It is stiill smaller than the other drake that I wanted to keep as the breeding drake. That is bizarre! I know chicken hens can have this happen, but I didn't know that ducks did too. WOW! They are all a year old this month, by the way.
I remember last year the ducks were a little slow to becoming fertile, but out of a dozen and a half or so, which is roughly 2 1/2 weeks worth, I haven't gotten anything from the Pekin eggs. The Call duck has only given me about 10 that went in so far, and so far nothing there either. I have 2 drakes with her since the other female got killed by a coon shortly after I bought them last fall. I have them in a hutch I built just for them so they would be safe and couldn't fly away.
Maybe going back to straight duck/goose feed will make a difference. I have been feeding lay crumbles/mash with cracked corn added in, which is what the ducks last year were getting when they started laying and it worked. Well, at least I have the ducks I bought, even if I don't hatch any, but it is a waste of time and money to keep them around for a year and not get anything out of them to re-coop my expenditures.