Place chicken in large pot and add water to cover (about 3 quarts). Add vegetables and salt and bring to boil. Reduce heat and simmer until chicken is tender and separates easily from the bone.
Remove chicken from stock and set aside. Reserve stock. Shred or chop chicken. To make the roux, melt butter in 3-quart saucepan over low heat. Stir in flour and cook for 1 or 2 minutes. Bring 8 cups reserved chicken stock to slow boil and gradually stir into the roux.
Simmer until soup takes on a glaze, about 15 minutes. Add pimientos, green pepper, 1/2 cup shredded or chopped chicken and ground pepper. Simmer for few minutes, stirring constantly. Serve in heated bowls. Use remaining chicken in salad or crepes