I purchased three muscovy ducks in the fall, the seller thought one male and two female. I see no difference in size anymore, and I wonder if I have all three males or all three females. They are approximately 7 months old. Today I found one pinning another on the ground (I think it was more of a fight than a mating). They all seem to make the same sound, that I am assuming is a hissing sound. They used to make a sort of cheeping sound but don't do that anymore. Can anybody tell the sex? Thank you!