They are VERY easy to do yourself.
Pot of water with some dish detergent in it on a hotplate. Don't boil, just get to a high simmer for about 24 hours. Check often and keep water full.
You can literally shake everyone off and out when the head is done. You'll have to clean out the brain and nasal cavities with a coat hanger or something but it is easy.
Cover with 40% peroxide for a couple of days. You buy at any beauty supply store.
I've done several myself. Don't over cook or the bone becomes really brittle and just falls apart.