First and foremost: DO NOT GIVE THEM MEDICATED FEED! These feed formulations are meant and developed for chickens. medicated water supplements the same thing.
I feed my ducklings an Honor product called Duck/ Goose/ Chick Nonmedicated Starter Grower. I kept the egg layers on that till 20 weeks then put them on a layer ration. Any starter without medication and around 21 percent protien should do, but i like a little courser grind for them.
The meat ducks I switched to a Turkey grower crumble at 2 weeks, and then a pellet at 6 weeks. At 9 weeks they were about 10 pounds.
Ducks will shovel their food rather than peck and found the 1 gallon plastic ice cream tubs work the best for food and water after a couple weeks. In my duck brooder I have a 2 foot square cut out at one end and placed half inch screen, with a large pan underneath. Ducks are VERY messy drinkers, and you will have forever wet litter if you dont have a drainage system.
Once the ducks leave the brooder I use 3 gallon rubber tubs with 2x4 wire cit out and covering the tops so they cant use their drinking fountain as a toilet as well.
Hope this helps.