Place the whole chicken in a large heavy-bottomed pot and cover it with cold water, enough to submerge completely.
Bring the water to a gentle simmer over medium heat, skimming off any foam that rises to the surface to keep the broth clear.
Add diced onions, sliced carrots, celery, a few sprigs of thyme, and a splash of olive oil to the pot. Stir briefly to coat the vegetables with oil.
Reduce the heat to low, maintaining a gentle simmer, and cook for about 45 minutes, until the chicken is tender and the broth is flavorful.
Carefully remove the chicken from the pot and set aside to cool slightly. Strain the broth through a fine sieve into another container, discarding the solids.
While the broth cools slightly, shred the chicken meat off the bones using two forks, then return the shredded chicken to the strained broth.
Squeeze fresh lemon juice into the broth and stir in salt and pepper to taste, adjusting the seasoning as needed.
Bring the soup back to a gentle simmer and cook for another 10 minutes, allowing flavors to meld and the vegetables to soften slightly.
Finish by stirring in chopped fresh parsley for a burst of freshness and bright aroma.
Serve the hot chicken soup in bowls, garnished with additional herbs and a slice of lemon if desired, alongside crusty bread or crackers.
