Here is cdc from wild ducks, which is all I use anymore. I think they trap more air. You basically get a few shades of gray(dun). You'll get different shades from different ducks. A mature hen mallard will have dark brown. I tie a lot of flies using just this to float it, for an 18 or 20 you don't really need anything else. Blot it when it gets wet and you're back in business. The last picture is a black duck and shows you where to find it, a mature bird will have more than a juvenile one. These aren't really long like the domesticated duck feathers that are sold in various colors, maybe 3/4 to 1-1/2"s.