Place chicken thighs, 8 cups water, bay leaves, peppercorns, and 1 teaspoon salt in a large (6-8 quart) stockpot. Bring to a boil over medium-high heat, then reduce heat to low, cover, and simmer for 25-30 minutes, or until chicken is cooked through and tender.

Carefully remove chicken from the pot and set aside to cool slightly. Strain the broth through a fine-mesh sieve into a separate bowl or pot, discarding the bay leaves, peppercorns, and any solids. Once chicken is cool enough to handle, remove skin and bones, then shred the meat into bite-sized pieces. Set aside.

Clean the stockpot if necessary. Heat olive oil over medium heat. Add diced carrots, celery, and onion. Sauté for 8-10 minutes, stirring occasionally, until vegetables are softened.

Add minced garlic, dried thyme, and crushed rosemary to the pot. Cook for 1 minute more until fragrant. Pour in the strained chicken broth and the additional 4 cups of low-sodium chicken broth. Bring the mixture to a simmer.

Add the shredded chicken and wide egg noodles to the simmering soup. Cook for 8-10 minutes, or according to package directions, until noodles are tender. Taste and season with additional salt and freshly ground black pepper as needed. Stir in fresh chopped parsley just before serving.