Mix all the meatball ingredients together using clean hands, then shape it into 16 equal-sized balls.
Put the meatballs in a crockpot.
Add the crushed tomatoes, tomato paste, onion, garlic, oregano, salt, black pepper, and red pepper flakes together to a mixing bowl.
Stir with a wooden spoon until just combined to make the sauce.
Pour the sauce over the meatballs to cover them.
Put the lid on the crockpot then cook for 3 hours on low or 5 hours on high.
Break the spaghetti into pieces then scatter it over the meatballs.
Pour in the chicken broth and stir the contents of the crockpot until everything is well combined and the spaghetti is submerged.
Cover and cook for 1½ hours more on a low setting, stirring every half an hour.
Add more chicken broth if you need to.
Serve the spaghetti and meatballs with fresh parsley and shredded parmesan cheese.