Mix all the spices and stuff together in a bowl.
Rub it all over the chicken. I put some under the skin as well, just cause, well, that's a gross thing to do but makes it worthwhile!
Chop up your onion into chunks and place it at the bottom of the slow cooker. Put the chicken on top.
Stick the slow cooker on high and cook for about 4 or 5 hours - the chicken just falls off the bone.
After you eat, stick some water, carrots, more thyme, bay leaf, another chopped onion and celery into the cooker and make a really tasty stock overnight.