Add the chicken broth, ham hocks, carrots, celery, onion, dried thyme, and black pepper to your slow cooker. Cover and cook on LOW for 8 hours.
After the cooking time is up, remove the ham hocks onto a plate. Remove as much meat as you can, shred it with 2 forks, add this meat to the slow cooker. Discard the fat and bones.
I like to degrease the soup before I add my dumplings, I do this by using a ladle and carefully skimming the fat off, and discard. Then I take a half sheet of a paper towel and lay it over the top of the soup and quickly remove, this will get the last of the fat off the soup.
Turn the slow cooker on HIGH to keep your soup hot while you prepare the dumpling mix.
Mix together the Bisquick and milk until almost smooth, some lumps are ok. Using 2 spoons, drop the dumpling mix into the hot soup in the slow cooker. I do about tablespoon size, I use one spoon to scrape up the dough and another spoon to scrape off the dough from the other spoon into the hot soup. Spread out the dumplings evenly in the broth.
Cover and cook on HIGH for 30 minutes. Do not open the lid while the dumplings cook.