Place chicken breasts in a large pot. Add chicken broth, vegetables, and salt. Cover, and simmer gently until breasts are tender, about 1 hour. Remove breasts, cool slightly, and remove skin and bones, keeping meat in one piece. Cover well to prevent chicken from drying while you puree the broth: Increase heat; boil broth about 20 minutes, uncovered, to reduce. Put broth and vegetables through food mill, or whirl in a blender. Measure 1 1/2 cups broth-puree. Make Vegetable CrÃƒÂ¨me.