I have a duck (4 weeks old) that has been lying down a lot more than the others. When the others are eating, it will sometimes sit away from the others, or it will eat lying down. The others do not (I can't be sure if it's the same duck each time, however). A little over a week ago, one of them fell over a few times, but this hasn't happened recently (again, not sure if it's the same duck). I suspected niacin deficiency, but I have been supplementing this from the beginning. I started with brewer's yeast and ran out (it's expensive!). I've been giving these niacin pills: http://www.amazon.com/gp/product/B0011FWEMU?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00 I also have been occasionally using a B-Complex vitamin. The niacin I am using is NOT flush-free. I have read people variably saying to choose flush free or not to choose flush free. Which do I use? Also, I have noticed that the powder from the niacin and the vitamin doesn't always dissolve well in the water. I'm wondering if they are getting the right amount. Advice would be appreciated. I have also been giving fresh peas, romaine lettuce, and kale on occasion.