Hello! I have four ducklings, they are 10 weeks old. We have been giving our ducklings nutritional yeast in their food to give them the extra Niacin that they need. I have heard that ducks need to be on niacin their whole lives. I have also heard that they only need to be on niacin when they are ducklings. Can you guys tell me which is true? We have plenty for now, but I want to order more (if I need to) before we run out. Thank y'all.