In a 6-quart slow cooker, combine the chicken broth, onions, carrots, celery, minced garlic, bay leaves, thyme, salt and pepper, stirring to combine.
Rinse the chicken, trim any excess fat from the cavity and place it in the slow cooker. Cover the slow cooker and cook the chicken on LOW for 8 to 9 hours or on HIGH for 4 to 5 hours until the chicken is cooked throughout and has reached an internal temperature of 165ºF.
Transfer the chicken from the slow cooker to a cutting board. Remove the bay leaves from the slow cooker.
Turn off the slow cooker and skim any fat from the top of the soup. (See Kelly's Note.)
Add the noodles, stirring to combine. Allow the noodles to cook just until al dente, about 20 minutes. While the noodles cook, remove the skin, fat and bones from the chicken and shred the meat. Once the noodles are cooked, return the chicken to the slow cooker, stirring to combine. Taste and season with salt and pepper then serve.