Gather all ingredients. Preheat the oven to 250 degrees F (120 degrees C). Grease a baking pan with cooking spray.
Arrange chicken drumsticks in the prepared pan; sprinkle with Cajun seasoning, poultry seasoning, garlic powder, salt, and pepper.
Sprinkle flour on top. Spray chicken with cooking spray; cover the baking pan with aluminum foil. Bake in the preheated oven until juices run clear, about 2 ½ hours.
Remove foil and pour barbecue sauce evenly over chicken.
Continue baking, uncovered, until chicken is tender and falling off the bone, about 30 minutes more.
