Place all the ingredients into the slow cooker. If you choose to use the fortified wine or wine, you can omit the apple cider vinegar. Add water to the slow cooker or stockpot just to cover all the ingredients.
Turn the slow cooker to the high setting for one hour, then turn it down to the keep warm setting and allow to simmer on keep warm for six hours. If your slow cooker does not have a keep warm setting, turn it down to the low setting, but tilt the slow cooker lid to allow for some of the steam to escape to prevent the bone broth from boiling.
After six hours, turn off the slow cooker. Allow broth to cool slightly, and then begin to strain ingredients with a slotted spoon. Reserve meat, bones, and skin to be reused to make a second batch of broth. (Or just reserve bones and skin for a second batch of bone broth and eat the meat.)
Once all the ingredients have been strained from the broth, line a colander with a cheesecloth or flour sack towel and place over a deep pot. Use a ladle to transfer the broth from the slow cooker or stockpot into the lined colander. The broth will drain through the lined colander into the deep pot. This will help to strain out the small bits of meat, vegetables, etc., that were not strained out with the slotted spoon.
Once all the broth has been strained through the lined colander into the deep pot, transfer this pot to the refrigerator until the fat rises to the top and congeals. (Or you can use a fat separator to remove the fat before refrigerating. See video.)
Upon removing the bone broth from the refrigerator, skim off the fat that has risen and congealed at the top, and transfer the fat to a separate container to be used in other recipes. Transfer the broth to one or more containers with a cover that can then be refrigerated or frozen.
Depending on how you plan to use it, you can store the broth in multiple smaller containers or one single large container. This bone broth will stay fresh for 3-4 days when refrigerated. If frozen in the freezer of a refrigerator, it will stay fresh for 6 months. In a separate freezer that is not opened frequently, it will stay fresh for up to 12 months.