Place the chicken breasts in the bottom of the slow cooker. Pour the chicken broth over the top.
Add the cubed cream cheese, chopped artichoke hearts, spinach, garlic powder, and salt. Do not stir.
Cover and cook on low for 6 hours or until the chicken reaches an internal temperature of 165 degrees.
Remove the chicken, shred it with two forks, and return it to the slow cooker. Stir in the Parmesan cheese until the sauce is smooth.
Cook the penne in a separate pot according to package directions. Drain and add it to the slow cooker. Stir everything together until well combined.