Place the black beans and the 4 cups of water in a large stockpot.
Cover and let boil for 2 minute.
Turn off the heat and let stand, covered, for 1 hour.
Remove the lid, and add the rest of the ingredients, EXCEPT the vinegar, salt and pepper. There should be enough liquid (chicken stock and water) to just cover the beans. If needed add more of either liquid to cover.
Cover and simmer until the beans are tender, about 2 hours.
Take out the hocks and remove the meat from the bones and fat.
Return the meat to the pot; discard fat and bones.
Add the vinegar, salt and pepper.
Simmer long enough to heat the vinegar throught the beans.