Most fly tiers use the saddle/hackles from specially bred fowl. They can go for up to a couple of hundred bucks from just 1 bird. The best of these hackle bred birds are at Whitings in the west. The owner is a poultry scientist(geneticist) who has spent many years developng these special poultry, his genetics are captive and no one ever gets a live bird from there; he does sell some which are taxidermy specimens, even PINK birds. There are a few smaller breeders who are coming along with their breeding programs but it is a long road even for the genetics experts.
I have sole a few saddle/hackles to local tiers and even shipped a few from my Phoenix & Sumatra fowl but they would be considered low grade and not very valuable.

Try Whiting hackle bred farms or ?? to see his web site, will try to look up the url.

try www.whitingfarms.com or just google whiting farms & youll get there.

Lots of people sell feathers on ebay. Just use the search feature and select "all categories". Besides fly tying, they are great in dried arrangements and also to refurbish vintage hats.