I've hatched out 7 lovely runner ducklings. They're all looking happy and healthy. My question is this. I'm feeding them non-medicated chick feed and they're growing fast and look great. I've read that adding brewers yeast and niacin are good to add to the diet, but then read this is mostly for larger breeds. I'm not sure what I should do since I cannot find what kind of additive I should use or even if it's necessary for these guys. Any help would be appreciated.