Place all the ingredients in a slow cooker and cook on high until boiling, then switch to low setting for 4-12hrs
Remove all bones and vegetables from the broth and strain into a large bowl.
Allow to cool then pour into individual jars ( I use a funnel for this).
Put jars into the fridge and leave overnight until the broth thickens and turns into a jelly consistency.
I keep all the vegetables which have soaked up all the amazing broth and either blend or chop into a soup,
Jars of broth can be frozen, just don't fill them to the brim otherwise they may explode.