It appears to be a game bird feed, I think I see pictures of a turkey, guinea, pheasant and quail? Anyway, I've never heard of that brand, but it'll be fine so long as it isn't medicated. It'll certainly meet their nutritional needs better than apples and banana.
What's the protein content?
This looks like great feed from what I can see. I think you have the "show" formula for "ratites? ( that is, Ostriches and emus , etc.)
Call the company and ask them. Sometimes feed can be cross-feed to another species. But I would ask first. I do see they have a
wide selection of duck formulas for different ages. Call them and see, smile.
Best,
Karen