Preheat the oven to 250 degrees. Line a baking sheet with parchment paper.
Peel the sweet potatoes then use a knife or mandoline to cut each sweet potato into 1/4-inch slices. Side Note: You can cut them lengthwise for bigger dogs and into coins for medium to small dogs.
Arrange them in a single layer on the baking sheet and bake for 2 1/2-3 hours flipping them halfway through baking until they are shrunken and dried out. Some smaller pieces may be a little crispy but still very tasty.
Let the sweet potatoes cool completely before storing them in an air-tight container in the refrigerator for up to 3 weeks or store them in a sealed ziplock bag in the freezer for a couple of months. Enjoy!