Preheat the oven to 425°F. Place the potatoes in a medium saucepan and cover with water by 1 inch. Add 1/2 teaspoon salt. Bring to a boil, reduce the heat, and simmer until the potatoes start to soften but are not cooked through, 5 to 6 minutes. Drain, then let sit in the strainer for 1 minute.

Pour or spoon the chicken fat onto a rimmed baking sheet and add the potatoes. Gently toss the potatoes in the fat to coat, then sprinkle generously with salt and pepper. Spread the potatoes into a single layer and bake, tossing occasionally, until golden brown all over, 25 to 35 minutes. Remove the potatoes from the fat, sprinkle with salt, and serve.