What's the trouble? Niacin? Other vitamins? Protein percentage? Did he say anything about possibly using the same feed for both and supplementing calcium for her? Dumor layer feed is TSC brand and is for both chickens and ducks. I believe that the 18% is $13 for fifty pounds.
EDT: This site may...
I raise Swedish ducks on a budget.
Ducklings begin on flock raiser (18% Dumor) until they're well-feathered to take the cold (usually about six or seven weeks), then I supplement with free-ranging (our pond is infested with snails, which the ducks swallow whole; they actually get more protein...