Prepare the green bell peppers by cutting the tops off (save the tops) and removing all the seeds and membranes. Set the peppers open side up into the crock pot.
Put the remaining ingredients EXCEPT the chicken broth in a large bowl and mix, breaking up the ground beef and pork and making sure everything is combined well.
Fill the peppers with this mixture, then set the pepper 'tops' back on the peppers. The peppers should be over-flowing with the meat mixture, so the top will just teeter on the top of the mixture, it won't fit down all the way.
Pour the chicken broth into the slow cooker around the peppers.
Set slow cooker to LOW, cover and cook for 7 to 8 hours, until peppers are tender and meat is cooked.
If using large bell peppers, 4-5 will work.
Use a meat thermometer to check the internal temperature.