I have an enormous Pekin drake, a Pekin duck, and 4 runner ducks. They are all 5 months old. The last two weeks, I noticed the smallest runner duck limping around. I thought it was a niacin deficiency, so I isolated her and gave her food with brewer's yeast while she recovered. Shortly after recovery, I noticed her limping again several days later. Earlier in the same day, I observed the Pekin drake mounting her and some of the other ducks. I believe now that this is what is causing the leg injuries. I'm assuming the answer is "no," but is there anything I can do to keep the ducks from getting injured in this way?