When fishing with Marc Petitjean some years ago someone shot a duck (illegally) up stream of us. As it drifted down we snaffled it. Here is a photo I took of him showing where the CdC feathers are located.
http://img.photobucket.com/albums/v2...ell/MPduck.jpg
As he showed you are lucky to get 3 or 4 really good feathers off a wild bird. His CdC comes from commercial ducks produced for the table. Farmyard ducks will produce better CdC for tying as they do not preen themselves as much as birds on water do. Collecting the oil in their bill damages the feathers (inconsiderate of the birds I know).
You should still get usable feathers from your wild birds. The ones from that one were. Apparently swan CdC is really amazing stuff. If you can get it.
Your wild CdC will be fine best of all its a free bonus. You'll have to do the sorting yourself but that is probably the largest part of the cost of commercial CdC.
Don't forget the very best CdC pattern ever. Our very own Hans' CdC and Elk. The only fly I have ever stopped fishing with as I felt it unfair on the fish.
Cheers,
A.