Add your bones to an 8-quart stockpot and cover with water.

Turn your stove on high and bring the water to a rolling boil. Turn down to medium-high heat, and continue to boil for 20 minutes.

Preheat your oven to 450 degrees.

Once the bones are done boiling, rinse them with cold water to get off any loose residue. Make sure to leave as much marrow in the bones as possible.

Place the bones on a baking sheet and put them in the oven for 30 minutes.

Flip them over and roast for an additional 15 minutes.

Put the bones (and any fat that came off when they were roasted) in a clean 8-quart stockpot, add the apple cider vinegar, and then fill up the pot the rest of the way with water, making sure to completely cover all of the bones.

Bring the water to a simmer, cover partially, leaving the lid tilted, and cook on the stove for at least 12 hours.

Make sure to replenish the water as it evaporates.

After you're done simmering the broth, remove the bones with tongs and place the pot in an ice bath to cool.

Put the pot in the fridge to chill for 36-48 hours.

Once the broth has fully chilled, it will have thickened and there will be a hard layer of fat on top. Remove the fat which can be used for cooking.

Place the broth back on the stove on medium heat and warm until it's thin.

Strain the broth through a cheesecloth over a mesh strainer and store it in the fridge or freezer.