Get a new vet.
Scratch and Peck is fine, if a bit pricy for my tastes. Their whole grain feeds should be sprouted, fermented, or at least served as a wet mash to ensure your birds eat the fines (that's the vitamin and mineral premix) and to discourage ther flock from picking favoirte grains/seeds based on pecking order.
Ask your vet what's wrong with "duck food" for chickens? I truly curious to hear what he or she might think, when all the studies put their nutritional requirements at VERY similar levels. Ducks need more niacin, but it doesn't hurt your chickens any. Ducks and other waterfowl benefit from about 1% more fat (4.5% +/- rather than 3.5%) but many commercial chicken feeds have fat in the 5.5-6% range. Ducks shouldn't exceed 24% crude protein, particularly pre-adult - but most people feed their chickens between 16% and 20%.
So, go ask... If the vet can't at least rattle off what I just did, you need a livestock vet, not a cat and dog vet, to provide advice for your flock.
