Place the bones (frozen or thawed) and the vegetables in a 6 quart slow cooker.
Pour apple cider vinegar over the mixture.
Pour filtered water over everything up to the top.
Set slow cooker to low for 12-24 hours.
Strain the broth and discard the soft bones and vegetables.
Refrigerate the broth until the fat floats to the top and hardens.
Remove the fat and discard it or save for later.
Store the broth in the fridge or freezer.
Notes
It's normal for the broth to look gelatinous, kind of like jell-o when it's completely cooled. It means it's holding all those nutrients from the bones and the vegetables!