I have 2 one month old pekin ducks. They were the only sexed pair at the store but they where not sure which were female or male, only that there was one of each. I have one of them that actually hisses. S/he does this when it sees the one week old that we have. The one they thought was male is always laying in the food dish and the other one is always peeking at his neck. The one that "roasts" in the food is way bigger then the other one. So I feel that the bigger one is the female because of the roasting in the food and the other one peeking his neck. The smaller one is the one that hisses and I believe is the male. Anyone have anything that might help me know if I am right?