Sweet Potato Chews -[Dog Treat Recipe] Preheat oven to 250 degrees. 1 large sweet potato,washed and peeled Slice up the sweet potato 1/4" thick. (I cut mine in half Keep in mind that they shrink as they dehydrate so don’t cut them too small). Put in oven for at least three and half hours. Make sure to turn them over at some point so they cook evenly. For crunchier, leave them in longer.