In a medium bowl soak your well toasted bread with the milk. Allow it to sit for about 10 minutes.
Meanwhile in a large bowl, combine the ground chicken, egg, spices, and seasonings very well.
Drain and discard the milk, then very gently squeeze the moisture out of the bread. Add the soaked bread to your bowl with the meat.
Thoroughly mix to combine well (I use my hands for this), then form into small meatballs, making about 14-16.
Heat your oil and ghee together in a large Dutch oven or stockpot, over medium heat. Add in meatballs and cook for about 6-8 minutes, or until nicely golden on all sides and mostly cooked through.
Add in the onion, then continue to cook for 3-4 minutes, stirring gently and carefully not to break the meatballs.
Meanwhile, in a small bowl, whisk the Arrowroot/cornstarch with a few tablespoons of the broth until smooth with no visible lumps.
Add in the coconut aminos and mustard then whisk until combined. Set aside.
Add your remaining bone broth to the soup, together with the milk, vinegar, and brown rice.
Bring to a boil, then reduce to a simmer, and cook until the rice is tender, about 20-25 minutes. Very gently stir through the bottom of the pot every now and then, to avoid the rice catching on the bottom of the pan.
Once your rice is cooked, add in your Arrowroot/cornstarch mixture to your soup and stir well to combine.
Allow your soup to simmer on LOW for about 5 minutes, the Arrowroot/cornstarch will help it thicken up a bit.
Season your soup to taste and garnish with fresh parsley and red pepper flakes.