Hi everyone, it's been too long since I had baby ducks so I'll throw out an easy question for the "pro's"-one baby-3 weeks old approx.- has a black bill the other one is yellow or the same color as the duck. Does this mean one is male and the other is female? I don't know what breed they are as they were given to me and they have so many they didn't know who mated with whom. Thanks for any help.