Do a google search on Turkey Farms in your area and visit or write to them asking for feathers. Most of them treat the feathers as waste.
Unfortunately, unless you're going to deal with a local farmer growing white domestics, the feather quality on most commercial birds is very poor (they aren't exactly grown for their feathers ).
I found a commercial farm and got a trash bad of feathers (they processed their own turkeys) straight out of the steamer or whatever they put the birds into to get rid of the feathers. Most of them were not good enough to use for fletching.
