Coat the inside of a slow cooker with cooking spray.
Rub the BBQ spice all over the drumsticks, then place the drumsticks in the slow cooker in layers.
Pour 2 cups of BBQ sauce into the slow cooker. Gently toss to coat.
Cover and cook on low for 5-6 hours or high for 3-4 hours.
Preheat the broiler.
Remove the chicken drumsticks from the slow cooker and place them in a single layer on a sheet pan coated with cooking spray.
Brush the remaining ½ cup sauce over the drumsticks. Broil for 3-5 minutes or until edges are starting to brown and crisp, then serve.
