Make the homemade chicken broth: Place the whole chicken or chicken pieces in a large stockpot. Add the quartered onion, roughly chopped carrots and celery, garlic, bay leaves, peppercorns, and salt. Cover with 8 cups of cold water. Bring to a boil, then reduce heat and simmer for 1-1.5 hours until chicken is tender and falling off the bone.

Strain and prepare ingredients: Remove chicken from broth and set aside to cool. Strain the broth through a fine-mesh sieve into a clean bowl, discarding the solids. Once chicken is cool enough to handle, shred the meat and discard skin and bones.

Sauté vegetables: In the same stockpot, heat olive oil over medium heat. Add diced onion, sliced carrots, and celery. Sauté for 5-7 minutes until vegetables begin to soften.

Combine and simmer: Add the strained broth back to the pot along with the shredded chicken, thyme, and parsley. Bring to a simmer and cook for 15 minutes to allow flavors to meld.

Add noodles: Add egg noodles and cook according to package directions until al dente (typically 8-10 minutes). Taste and adjust seasoning with salt and pepper as needed.

Serve and enjoy: Ladle the hot soup into bowls, garnish with fresh parsley, and serve immediately. This homemade chicken noodle soup is perfect with crusty bread or crackers.