Heat the oil in a large pot over medium heat. Add the onion, celery, carrots, garlic, bay leaf, parsley, salt, pepper, and sage. Cook for 5-7 minutes, until the vegetables are starting to soften.
Add the chicken stock to the pot and bring to a boil.
When the stock is boiling, add the pasta and cook according to package directions.
Add the chicken when there is about 2 minutes left for the pasta to cook.