Add all ingredients to the slow cooker.
Pour enough water over the ingredients until the pot is full, except for a couple of inches from the top.
Place the lid on the insert and set to low for 8-10 hours. For darker, richer stocks, repeat for another 8-10 hours or until desired color is reached.
When ready, let the stock cool in the pot for an hour.
Place a fine mesh colander over a large bowl, gently pour the liquid from the pot over the colander. The finer the mesh, the fewer bits from the pot end up in your jars. Some contents may escape in the colander, but that's ok. You may to empty the liquid in stages if your bowl or colander isn't big enough to hold the entire pot's ingredients.
When the stock fills the bowl comfortably enough to lift the bowl to fill your storage jar, pour the bowl's contents into a funnel placed over the jar's mouth. Move the funnel to the next jar and repeat. This is the best way to avoid stock running all over the counter. Alternatively, you could carefully strain the liquid into a wide pitcher with a no-drip spout to then divide among jars.
Repeat the strain/funnel method until all the liquid is gone from the pot. A typical large crockpot or Instant Pot yields anywhere from 3-4 quart mason jars or 2-3 two-quart freezer bags of stock per recipe.
IF KEEPING IN FREEZER BAGS, continue to use a 1 quart mason jar, but dump the filled jar (or two) into your freezer bag so you have a solid measurement of how much stock is in the bag. Seal the already-labeled bag (bag should not be full to save room for its inevitable flat state in the freezer) and place it flat on a cookie sheet or some other flat surface in the freezer. If you have more than one bag for the freezer, don't stack them in the freezer yet - they will freeze together. Lie them separately to freeze individually. Once frozen you can arrange them like books on a shelf, or a big stack, depending on your freezer organization.
Discard the pot contents: either add the spent bones to a freezer bag that heads to the trash on trash day, like we do, or compost what you can.
The stock will keep in the refrigerator for a week, or 6 months in the freezer.