I have tried all over to find info on this and can't seem to get any. I got two blue swedes from the feed store about mid-April. They thought they were girls, but couldn't guarantee. I then got two ducklings from a classroom hatch born at the end of April. The blue swedes are huge, but still no quacking from either. Sometimes I think I can see a curly feather on one, but not always. The class ducklings are either straight Khaki Cambell or a mix of Khaki Campbell/Runner. One is Khaki colored and quacking up a storm, the other is black and still quiet. The class ducks still have their soft baby feathers in. The Swedes are only a couple weeks older but they are as big as my hens and have been feathered for several weeks. I think my khaki is a girl, from all the quacking, but I can't figure out on the Swedes. Neither one make any noise. I picked one up yesterday and he (probably) did a hoarse quack. Every site I check tells me a different identifying feature. Some say orange feet mean male, some say feet color doesn't matter. Same with bills. One said males have greenish tint to their heads. I'm really hoping that I don't have three males and only one female. That would NOT work, poor little girl! Ouch! Any thoughts? btw, they have a 60x10 run and they love to hang out on these boards.