Combine the dried spices in a small bowl.
Loosely chop the onion and place it in the bottom of the slow cooker.
Remove any giblets from the chicken and then rub the spice mixture all over. You can even put some of the spices inside the cavity and under the skin covering the breasts.
Put prepared chicken on top of the onions in the slow cooker, cover it, and turn it on to high. There is no need to add any liquid.
Cook for 4 – 5 hours (for a 3 or 4 pound chicken) or until the chicken is falling off the bone.