These folks are often worth a try for less common materials, whether fur or feathers. Their inventories seem to fluctuate quite a bit depending on what you're looking for.
Right now, they seem to have a lot of ruffed grouse though..
https://www.hideandfur.com/inventory/3072.html
On edit; They are often pretty expensive as well in general as they mostly deal in full skins or hides. Sometimes, the prices are not too bad though, as currently seems to be the case with the grouse.