I have a duckling who is not doing very well. She has been kinda down lately. I pulled a clump of poop off her vent(?) (Is that what it's called for ducks?) and her whole underside of dirty. She is a couple months old, and much smaller than her siblings. She is a white/blue muscovy. I have her in a lukewarm bathtub to loosen the dirt and poop on her underside. I can't tell is she has a kink in her neck or not, but I want to give her some niacin in case. I only have the time release kind. I'm trying to feed it to her in feed (as opposed to in her drinking water). But it's hard to know how much she is getting this way. Can you overdose a duckling on niacin? Also, any advice on getting her better would be much appreciated.