Fill your slow cooker with bones (free range if possible. You can use chicken frames or bones/duck/turkey/beef). If you don't have a slow cooker you can also do it in a stock pot. Leave it on low for the day.
Fill the pot so the bones are completely covered - add in an extra 2-3 inches of water on top (filtered water)
Add raw apple cider vinegar (you can use lemon juice as a substitute). For a regular sized crock pot use 2-4 tablespoons of apple cider vinegar
Turn slow cooker on to high for the first hour then switch to low for the next 23 hours.
When the broth is finished strain the bones (DO NOT give the cooked bones to your pet)
Leave it to chill then put it into the fridge
Once the broth has chilled in the fridge skim any excess fat off the top
If the broth has a jelly-like consistency when it is cold, well done you have done a great job!
Freeze into small containers or ice cubes for use when needed.
The jelly on the broth means that you have lots of gelatin in the broth. This is what you want as this is what will help your pets joints and any tummy issues including leaky gut. The gelatin plugs the holes in the leaky gut. The more jelly-like the better!
If you find your broth isn't jelly-like, don't worry, it just means that you didn't add enough apple cider vinegar. In your next batch just add in a bit more.