Poultry swaps would be a good place. One every 2 nd Sat at local sale barn. Dad kept pheasants around the farm, and a pair of peacocks. There were std pheasants, Amhurst, and Golden. The male peacock dropped it's tail feathers all over and I would stick them in a vase for later use.
Banty roosters made for fair hackle too. They were in coops and easy to catch.
Local cemetery kept birds in a display at the entrance, usually pheasant and peacocks. I know some that used that as a source of material for flies.