According to Dave Holderread, Purina Flock Raiser is a complete diet for young waterfowl. He is almost always right.
However, this is one case where I have some doubt, because I know at least one case where someone raising some babies I had hatched was using Flock Raiser and had niacin deficiencies (which were easily corrected by adding niacin to the diet).
I asked Mr. Holderread about that when I spoke with him a few months later for an article I was writing. He said that even national brands use different formulations in different parts of the country, based on what is cheapest to use locally. He recommends Flock Raiser because they use it without problems and he doesn't know of any problems elsewhere, but he says it is possible that in our area, something about the formulation makes it less suitable. On the other hand, it's also possible that a mistake was made with the particular batch the gentleman was using, and that he would have been just fine with any other batch of Flock Raiser.
So, that's a long-winded answer. The short answer is yes, it's probably a perfectly adequate diet without additional niacin. But always be on the look-out for symptoms, just in case.
P.S. A picture of a duck on the package does not necessarily mean it's a complete formula for ducks. Many chick feed brands use ducks on their packaging too, even when they are not complete feeds for ducks. Just FYI.
