I am really happy you want to do your best to correct the problem. If he is walking different too, it is very serious indeed. If you can't find the right supplements at your local stores, you can order them online. Do you have access to
Amazon.com? I was more interested in the nutrition contents of your chicken feed. A lot of people are able to feed their ducks chicken feed, it just needs some vitamins added. Ducks have different needs form chickens. There are a lot of chicken feeds. Is this a meat grower feed, layer feed, flock raiser, etc?
If you are starting treatment this young, I think there is a good chance he will recover. If you were to change nothing he would most likely start having deformed legs, and the wings would be irreversible. It changes the bone structure of the wing, and once the bone hardens, it is permanent. That is why I am so happy you came for help early! Yay!
A few months ago, someone dropped a huge male pekin over my fence. He had a very bad angel wing, and was severely malnourished. After a few weeks of proper feed and care, his health was vastly improved, but I couldn't do anything about the angel wing. It broke my heart.
Start today with leafy greens - chop them up and offer them in a dish with water. Also try any veggie or fruit you have on hand, get an idea if what he likes. Mine love peas, lettuce, squash, cucumbers, tomatoes and watermelon.
You can offer meal worms and crickets when he is older, also live feeder fish. But they are a treat. An adult duck should only eat 2 Tablespoons of meal worms a day. That is a small handful. A duck in the wild, or a domestic duck that is foraging in your yard will eat a wide variety of plants and bugs. They are able to supplement their diet themselves. They seem to know what they need. My ducks never eat grass, but when I offer them a treat of fruit or chopped meat or fish, they will take big mouthfuls of grass between bites. They are supplemented with duck food at night.