Okay, I'm at a loss here. I've got 2wk old ducklings, one that is showing signs of niacin deficits. Somewhere between A and B in the diagram below. Trouble is, I'm feeding purina flock raiser, and have been providing 136mg niacin mixed with each gallon of water. I'm considering upping the niacin in the water but I don't know what the upper limit should be since flock raiser should have niacin too. So now the question is, could there be another vitamin deficiency at play, or is this just this individuals ability to process niacin causing me headaches (I've read that some ducks may be worse at accessing the available niacin than others.) I've also provided Sav-A-Chick Electrolyte and Vitamin Supplement mixed in the drinking water, though only once in their two weeks. Your input is valued, thanks.