My 6 week old babies have started to quack, but still make baby sounds too. I want to know if I have males or females. I have one cayuga, one khaki campbell, and one mallard/rouen. Our mallard/rouen is working on feathering out and we have noticed that it has a white ring starting to form around it's neck. Does this mean male? The white ring is mostly downy feathers. Is sexing by quack different by breed?