Yes one of my ducks who we thought was a male ended up being a female. I honestly don't know how to sex birds, I just assumed she was a male because she never laid eggs until now. We found this out because we went into her coop the other morning to let her out and we found an egg. This has been happening everyday now for the past week and half. There are no other ducks in their with her, so it is her who is doing the laying. I just find it odd that she has never laid eggs until now. She's a little older then two years old and has never laid until now. What concerns me is the fact that all of the eggs she has been laying don't have shell on them, just the membrane. Should I be worried? Has this ever happened to anyone else before? Should I contact my vet about this?