In my personal experience, the AW was presumably due to genetics. Wild flocks of ducks often developed AW and in a lot of the cases that is due to consumption of unhealthy foods ( bread, snack foods, etc).
As long as you are feeding them a nutritionally correct diet, and they are getting plenty of exercises I would not blame this on your management practices.
At this age, bandaging will most likely be ineffective. Cutting the feathers would likely be the best option simply to prevent the feathers from getting caught in things, and to provide better aesthetics.
As far as cutting, I would secure the duck, and gently spread the affected feathers out, and aim to cut all the primary feathers. These are the longest feathers of the wing and most of what is sticking out in the picture. If you notice the very base of the feather shaft appears purple, you will need to wait longer as there is still blood in the primaries.
Cut near/down to the line.