I want to be sure that we don't get angel wing. But I also want quick growth.
My birds have always had healthy growth on Flock Raiser but I don't raise meat birds so have never watched their weights closely.
I raise for eggs only.
Ducklings grow so fast that you probably don't need to feed them a special diet like you would for chickens ( layers vs. broilers).
I fed my current batch of ducklings free choice 20% soy free from scratch and peck feeds and supplemented daily with greens (clipped grass, greens, peas) in a dabbling bowl and top dressed food one time a day with a handful of (different choice daily) steamed potatoes, carrots, cottage cheese, spirulina supplement with flax & dried insect pupae, canned dog food so i could get them sued to the thing theyl'l left when they're added to by adult ducks pen. I have not fed them beets or water melon yet because I don't want to clean that mess out of the bath tub ;)
You may find a meat duck ration in storey's guide to ducks. I can't confirm for you because I loaned my copy to new duck keeper in town.
It's a good reference so it's worth buying.
I've brooded two sets of ducklings in the tub. We're very slowly completely renovating a farm and farm house that literally haven't been updated since they were built in the 50s :). THe bath tub works great for them because the water mess goes down the drain and I can wash their other mess down daily as many times as it needs it :).
Because of the other projects we have to complete we won't have electricity down by the duck yard for a loong time yet. Where I live it is still getting down to the 30s at night and freezing occasionally so they can't be outside until they're fully feathered.
Dog food provides animal protein. It's a calorie dense food source and I started feeding it to my layers once they started laying in December. I think they are healthiest and happiest when they are getting animal protein in their diet. i have not had any eggs with off colors or off flavors.
My hens particularly enjoy venison and tripe.
Yes, it's canned dog food. I'm using ziwipeak brand because they don't add in weird chemicals like some more mainstream brands. MY ducks wouldn't eat dry dog food even if i ran it through a feed mill first.
Another animal protein source may work for your ducklings. My adult ducks do not! like fish meal or crab meal so they end up wasting any feed that uses it as the protein source.
I found out that they love venison after I ruined a venison shoulder.