Place the beef stew meat and lamb stew meat into the slow cooker.
Add the potatoes, onion, and carrots on top of the meat.
Pour the beef broth over everything.
Sprinkle in the thyme, rosemary, bay leaves, salt, and black pepper. Stir once to combine.
Cover and cook on low for 8 hours.
Remove the bay leaves. Ladle the stew into bowls and top each serving with fresh parsley.