Someone told me that you can tell the sex of a duckling by the color of their legs (depending upon the breed) - specifically mallards. They said that males have the orange legs while females remain black. I had never heard of this before and it sounded nuts to me. Then I went out and checked my grown ducks as well as some of the wild ones at a pond near by. The females all had black legs and the males were orange. Of course, this was just a small sample of ducks and in no way backs up the hypothesis - I just found it interesting enough to pose the question here among those with more expertise than me. So, anyone ever hear this theory and/or know whether or not it's true?