In a large bowl, mix the ground beef and chicken together well with your hands. Add the onion and reserved juice and mix to combine.

In a food processor, grind the rice until it resembles coarse sand. Add 2 cups of the ground rice to the meat mixture, along with eggs, salt, pepper, and turmeric, mixing well. Cover and refrigerate while the broth cooks (or up to overnight).

Place the soaked chickpeas on a large towel and cover. Using a rolling pin, roll over the chickpeas to remove the skins (they may split, it’s ok). Set the chickpeas aside. If you’re using canned chickpeas, skip this step and add your chickpeas in step #6. 

Place the beef bones in a large pot and cover with water. Bring to a boil and when the bones release their impurities after boiling for 10 minutes, remove from the heat and drain the bones. 

Return the bones into the rinsed pot and cover with 6 cups of chicken broth. Add the chickpeas, onion, and turmeric.  Bring to a boil and lower to a simmer. Cook for 3 hours, skimming frequently. Add more chicken broth as needed, making sure the ingredients are fully submerged. 

After the broth is cooked, form the meatballs: Divide the meat mixture into 8 portions, and roll into large baseball-size balls. Gently drop into the soup. If you are using canned chickpeas, peel and add them into the pot here.Bring to a simmer and cook for another 60-90 minutes until they are fully cooked through. 

To serve, place a few cheftes, beef bones and pieces of onions  into an individual bowl and top with a ladle full of broth. Serve hot.