Thank you for the resources! 
I had to double check - we’ve had wild turkeys in the yard, and they leave some beautiful big feathers.
The MBTA also does not apply to:
…
(2) Species native or nonnative to the United States or U.S. territories that either belong to families or groups not referred to in the Canada, Mexico, and Russia Conventions or are not included by species name in the Japan Convention. This includes the Tinamidae (tinamous), Megapodiidae (megapodes), Cracidae (chachalacas), Odontophoridae (New World quail), Phasianidae (grouse, ptarmigan, and turkeys), Pteroclidae (sandgrouse), Heliornithidae (finfoots), Burhinidae (thick-knees), Glareolidae (pratincoles), Todidae (todies), Psittacidae (parrots), Psittaculidae (Old World parrots), Meliphagidae (honeyeaters), Dicruridae (drongos), Monarchidae (monarchs), Pycnonotidae (bulbuls), Scotocercidae (bush warblers and allies)…
If I’m reading it correctly, it sounds like turkey feathers are okay to collect 
Thanks again for this addition, Megan and Artemisia - it’s good to be aware of.