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 also cut them lengthwise for bigger dogs and into coins for medium to smaller dogs.
Arrange them in a single layer on the baking sheet and bake for 2½-3 hours, flipping halfway through, until they have shrunken and dried.Side Note: Some smaller pieces may be a little crispy but still very tasty.
Let the sweet potatoes cool completely.
Store them in an airtight container in the refrigerator for up to 3 weeks, or in a sealed zip-lock bag in the freezer for a couple of months. Enjoy!