My mallard is like 3 weeks old maybe 3 1/2 weeks old and still has larger then when I got him but little nubbies I call them for wings. They look so funny
Looking back on pics of my mallards, it seems like their wings started to feather about 4-5 weeks, and by 7 weeks or so they were big enough to fly/glide.
Oh your little fluffy friends will grow so quickly. Take pictures now before they begin to feather. They feather gradually and will go through periods where he/she seems to grow feathers in one spot. Then suddenly you'll notice tail feathers, then wing feathers... then start to really notice the little feathers on the neck and head. It's fun to watch a duck grow feathers.