In a 3-quart soup pot, simmer stock. Add chicken, and poach until opaque and firm, about 10 minutes. Transfer to a plate. Add carrots and fennel to the broth, and cook until fork-tender, about 10 minutes.
Add chopped greens and beans; simmer. Shred chicken into 1-inch strips with your hands. Add to the pot, and simmer until chicken is heated through, about 2 minutes. Season, to taste, with salt and pepper. Ladle into 4 shallow soup bowls, and serve.
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