Preheat Oven To 350º and line 2 baking sheets with parchment paper. Set aside.
In a large mixing bowl, whisk together the brown rice flour and coconut flour.
Make a well in the center of the flours. Add water, egg, and coconut oil. With a spoon, mix the ingredients until they go from wet to crumbly looking. Then, using your hands, knead the dough for several minutes, eventually forming a dough ball.
Sandwich doughball in between two pieces of parchment paper. With a rolling pin, roll dough to about 1/4" thick. Stamp with cookie cutters and place biscuits on the baking sheet.
Bake in 350º oven for 20. Once the timer goes off, flip the treats over and make another 5 minutes. Keep an eye on them as everybody's oven can be different which could alter baking times.
Transfer treats to a wire rack to cool.
Notes
Store these treats in an airtight container in the refrigerator for up to 2 weeks, or in the freezer for 3 months.