1. Combine chicken stock, bourbon, honey, and thyme sprigs in a small saucepan. Bring to a boil; reduce heat, and simmer 15 minutes or until liquid is syrupy and reduced to 1/3 cup. Discard thyme. Whisk in mustard and green onions. Divide glaze in half.
2. Preheat grill to high heat. Combine black pepper, salt, and ground red pepper; sprinkle over chicken drumsticks. Place drumsticks on grill rack coated with cooking spray. Cover and grill 3 minutes or until charred; reduce heat to medium. Grill 18 minutes or until a thermometer inserted into the thickest part registers 160°, turning occasionally, and brushing drumsticks with half of the glaze during the last 4 minutes of cooking; use the rest for dipping.