Heat oil in large pot over medium-high heat. When oil is hot, add onion, carrots, and celery and season with salt and pepper. Sauté until softened, about 5 minutes. Add chicken, thyme, bay leaf, parsley, broth, and water. Bring to a boil.
Add rinsed farro and return to a boil. Reduce to a low boil, cover and cook for 15 minutes or until farro is tender. Taste for seasonings. Add salt and pepper as necessary. Add water if it has become too thick (we love ours super thick, more like stew).