Preheat oven to 425ºF. Prepare a baking sheet by covering with foil and spraying with cooking spray.
Combine the salt, garlic powder and black pepper in a small bowl. Season the drumsticks on all sides with the spice mix.
Place on the prepared baking sheet. Bake on the center rack in the oven for 30 minutes, flipping the drumsticks over half way through.
Combine the barbecue sauce, red pepper flakes and apple cider vinegar.
After 30 minutes. Remove them from the oven and brush with the barbecue sauce mixture on all sides. Bake for an additional 5-10 minutes until the chicken is cooked through to an internal temperature of 165ºF.
For the last 2-3 minutes, take out the drumsticks and move the oven rack to the top. Turn on the broiler and cook the chicken under the broiler for an additional 2-3 minutes, until the skin is crisp.