Dump the vegetables in the bottom of a 6-quart slow cooker or large soup pot. Place the bones in next. Tuck in the bay leaves and sprinkle salt and drizzle the vinegar over the bones. Add enough filtered water to cover everything completely.
Program the slow cooker to cook on low for 18-20 hours (you may have to set it for 10 hours and then come back and turn it back on…) or if cooking over the stove top, set the burner to low/simmer for same amount of time and cover the pot.
At 18-20 hours, off the top layer of “foam” (if necessary) and using tongs to hold one bone at a time and a spoon or spatula (something with a long, thin end) try to clean out the bones as much as possible and get all of the bone marrow out of each one. Then, pour the broth through a strainer and discard the solids (including the vegetables).
I suggest letting the broth cool and then pouring into glass mason jars/containers and placing in the fridge overnight prior to use. The fat will separate as it cools and end up at the top of the container – so when ready to use, scoop out that top layer and discard. Use immediately or place back in the fridge or into the freezer at this point.
The broth will keep in the fridge for a few days and in the freezer for several months. Be sure to let the broth cool completely before placing in the fridge or freezer.