My sister has 4 Muscovy ducklings around a week old. They are eating DuMOR chick starter. I know, I know. I need to add Brewer's yeast because the feed doesn't have enough niacin in it for ducklings and we're looking into that but what do I feed them after they are finished with the starter? Will Purina flock raiser work? It says I can feed the flock raiser to them now until laying age. When they start laying, what then? What age do I feed them what? There are no specifics on the websites I've looked at. This is our first time with ducks so we're not sure what to do. Thanks in advance!