Mix all the spices together in a bowl to make a rub for the chicken. If you don’t want your chicken to be spicy, then leave out the cayenne pepper and instead add in more onion powder, but note that the paprika will still make it slightly spicy.
Wash the chicken meat in cold water briefly. Place the washed chicken meat into the bowl with the rub, and rub the spices onto the meat thoroughly – try to get it under the chicken skin if you can. The wings and drumsticks work well here because you can rub the spices under the skin easily.
Place each piece of chicken covered with the spices into the slow cooker (no liquid required).
Set the slow-cooker on medium or low heat (325F if your slow cooker has a temperature controller), and cook for 5-6 hours or until the chicken meat falls off the bone (slow cooker times can vary dramatically).
You can serve the chicken with the bone on or take the bones out since the meat falls off so easily.