As I do not have Purina Flock Raiser or "duck" food available near me, I went with the suggestion from Holderread's. I mix in equal parts, organic chick starter and turkey/wildgame starter.
The point is that while one is low in niacin and the other very high in protein, by mixing them you cut down the protein amount but increase the niacin amount. It makes a very balances diet.
They get green every morning and evening before bedtime. They loves thawed frozen peas, spinach leaves, tomatoes and their new love is broccoli florets. They do not mess with the stems, just the florets. They also have free-range time so they get bugs and grass.
Once they begin laying, they will go on a layer food.