I have 3 Moscovy Drakes. No hens, none.. yet in a nest yesterday where the ducks sleep I found a duck egg. Yes, Im sure it was a duck egg. I even ask my room mate to look at and feel a chicken egg.. then.. I said "now hold this one" He said "wow, this one is different, its smoother" so.. its not just me.. its a duck egg. I know some poultry change sex, but how common is that in ducks?