Place all ingredients in a large slow cooker set on high. Bring to a boil, then reduce the setting to low for 12-24 hours. The longer it cooks, the better it tastes! Strain the stock through a fine mesh strainer or coffee filter into a large bowl, and discard the waste. If you don’t have a slow-cooker you can still reproduce this recipe on a stovetop, with a large pot on low heat.