Where can I buy brewers yeast? Locally, I have a Rural King (they don't have it), a Tractor Supply, WalMart, Meijer and other smaller stores. I'd rather buy local than order online if possible. My other question is how much do I sprinkle on the food and how often? I have 8 ducklings (Pekin & Rouen) 2-3 weeks old and two adult Rouens. None of them seem to be having any trouble, but I'd like to make sure they are getting the proper nutrients.