This is what I did when I got my ducklings earlier this year. Now I’m feeding them All Flock and add oats to it because the protein is slightly too high. We are limited to the feed I can get around here alsoI can’t get duck feed where I am either
I use starter chicken feed ( non medicated ) for first 3 weeks then switch to grower feed
I add nutritional yeast 1 tbs ti 1 cup feed for first 10-12 weeks to help with niacin
I don’t give any treats till 2-3 weeks when I can also provide grit so they can digest the foods
I’m not able to get the chick grit here and it’s why I wait a few weeks till they can handle the little bigger grit size