To assure that your ducklings get enough Niacin over their first 10 weeks or so you can get Brewers Yeast (not the stuff you make bread with) at most health food stores or places like GNC. Just sprinkle it over their food each feeding. You can also get the niacin pills that Walmart sells for dogs and grind them into a powder if you have a hard time find brewers yeast. Any mixed flock feed will do fine as will most chick starters if you have a hard time finding feed specifically formulated for ducks.I cannot find any information on manna pro gamebird/show bird starter. Does it have enough niacin for ducklings? That is the only available starter feed for ducks i can find around here.