Preheat grill on medium heat for 30 minutes. In a large bowl, toss the raw drumsticks with the vegetable oil, Salt, and Pepper. Spread drumsticks out evenly across the hot grill. Turn them every 2-3 minutes to ensure the drumsticks cook evenly, and do not burn. The drumsticks should take 17-20 minutes depending on size and temperature of grill. To ensure the drumsticks are fully cooked, insert an instant read thermometer into the thickest part of the meat alongside the bone. Bone-in chicken should be cooked to 175° F to ensure the bones are cooked through.