Hello! I have used BYC for a while looking for answers to help my ducks, but when I couldn't find an answer specifically for my girls I decided it was time to join. I have two female runners that are almost 2 years old. I have noticed, only when they are laying, that they seem to have some problems. During the day their legs will sometimes begin to shake and they will use their wings to try to hold them up, and eventually they lay down. I don't think they are sick or have a niacin deficiency because it only occurs when they are laying. Over the past couple of months when they stopped laying they did not do it at all, but now that they have started laying again, their problems have returned. Sorry for such a long post! I want to help my girls!