Using a paper towel to grip, remove skin from chicken. In a large bowl, toss chicken with buttermilk, garlic, 2 teaspoons salt, and teaspoon pepper. Marinate at room temperature 30 minutes (or refrigerate up to overnight).
Preheat oven to 425 degrees. In a food processor, pulse bread until coarse crumbs form. Transfer to a rimmed baking sheet and toss with oil. Bake crumbs until golden brown, 8 to 12 minutes, tossing twice. Transfer to a large bowl. Set a wire rack over sheet.
Working with one piece at a time, lift chicken from buttermilk mixture (letting excess drip off) and dredge in breadcrumbs, pressing firmly to adhere. Transfer chicken to rack.
Bake, without turning, until cooked through, 30 to 40 minutes, tenting with foil if browning too quickly.
Baking the chicken on a wire rack keeps the bottom of the pieces from becoming soggy. For spicier chicken, add a few shakes of hot sauce to the buttermilk.