Preheat oven to 350°F.
Place cooked duck meat in a food processor and pulse until the meat is finely ground.
Add the applesauce, melted duck fat, and egg. Pulse to combine.
In a large bowl, combine the rice flour, oat flour, oats, and blueberries.
Add the wet ingredient mixture to the dry ingredient mixture, a third at a time, stirring well after each addition. Add water, a little at a time, as needed until the dough holds together and is the right consistency for putting in molds or rolling and cutting.
Place dough into silicone molds or roll out dough and cut shapes with your favorite cookie cutter.
If rolling and cutting, gather scraps and re-roll and cut dough until all is used. Place the cutouts on a baking sheet.
Bake for 15-18 minutes. Remove from oven and allow to cool.
Store in an airtight container in the refrigerator.