This is fascinating. I have 2 KCs that are definitely male and female (impulse purchase at TSC in March from the "bulk duck bin") so I will be able to take a look at beans, feets, and heads tonight when I get home. I have 4 that are younger, I'm guessing 6-8 weeks. I *think* the oldest and largest is trying to quack - it's definitely not a rasp or a peep. I'm trying to gentle them so I don't think I'll be grabbing anyone's tail right now. They are so shy they won't even try my gift of white bread as a bribe. I'm hoping to get at least one more female for a total of 3 duck hens. The ducks lay so well through the winter - picking up the slack of my worthless chickens But unfortunately we're having an awful fox problem right now. I don't let anyone out of the electrified fence because that fox (or fox family) is waiting and watching from the woods. The other day I had a hen that flew over the fence (despite me telling her that's a bad idea) and he came around the back of the shed and nabbed her when I was 20 feet away. I was able to save her though...but I've lost a lot of hens and babies this year.