In a large stock pot, melt 2 Tbs butter over medium heat. Add onions, carrots, and celery. Sauté until tender. Add garlic and cook for about 30 seconds.
Mix in the thyme, sage, rosemary, oregano, salt, and chicken bouillon. Stir to combine.
Add the chicken to the pot and cover with water. Simmer for about 1 hour until chicken is done.
While the chicken is cooking, prepare the rice according to the package.
When the chicken is done, remove from the pot and cool. When it is cool enough to handle, debone the chicken. Cut the chicken into cubes and return to the pot.
Add the cooked rice to the pot and stir. Heat until soup comes to a simmer.
Mix the cornstarch into the milk. Be sure to stir thoroughly to avoid any clumps.
Melt butter in a heavy bottomed pot. Stir in the milk mixture and cook until the mixture thickens. Stirring constantly.
Pour the milk mixture into the pot of soup and stir until well combined.
Serve immediately.