Preheat the oven to 350°F and line a baking sheet with parchment paper.

In a medium mixing bowl, combine the rolled oats and whole wheat flour and stir until evenly mixed.

In a separate bowl, whisk together the pumpkin puree, beaten egg, and water until smooth.

Fold the blueberries into the pumpkin mixture, gently pressing a few berries to release some juice.

Pour the wet mixture into the dry ingredients and stir with a sturdy spoon until a thick, sticky dough forms.

If the dough is too wet to handle, add a small amount of extra oats and stir until the dough holds its shape but remains soft.

Scoop about 1 tablespoon of dough for each treat, roll into a ball with your hands, then flatten slightly into a disc.

Place the discs on the prepared baking sheet, leaving a little space between each chew.

Bake for 20 to 25 minutes, or until the tops look dry and the bottoms are lightly golden.

Remove the baking sheet from the oven and let the chews cool completely on a wire rack before serving to your dog.