Remove the skin from the drumsticks. I do this by pulling the skin as far down as I can, then when I can pull any further I grab onto the skin with a paper towel and the skin usually comes right off. I did have to cut the skin off of a few.
Place the chicken into the slow cooker. Sprinkle over the garlic, cayenne, pepper, and ranch dressing mix. Pour over the Frank's Red Hot and the melted butter. Stir.
Place the lid on the slow cooker, and cook on HIGH for 4 hours without opening the lid during the cooking time.