In a large pan, cover the chicken with broth or water with salt to taste and simmer until tender, approximately 25 minutes. Drain and return the broth to the pan. Set the chicken aside.
Bring the broth to a simmer, add the carrots and potatoes, and cook for 10 minutes. Add the chayote and zucchini and cook for another 10 minutes or until the vegetables are just tender. Remove the vegetables from the broth and cut into large cubes. Set aside.
Put the tomatoes whole into the hot broth and simmer until soft but not falling apart, about 15 minutes. Remove and reserve the broth.
Put 1/2 cup of the broth into a blender, add the cumin, peppercorns, and oregano, and blend until smooth. Gradually add the tomatoes and blend until smooth. Set aside.
Heat the oil in a heavy skillet, add the plantain, and fry until golden on both sides. Drain well and reserve.
Measure 2 tablespoons of the oil into the pot in which you are going to cook the stew. Add the flour, stirring well to eliminate any lumps, and cook to a deep golden color. Add the tomato puree, stirring well to make a smooth sauce, and cook over low heat, scraping the bottom of the pan to prevent sticking, for about 3 minutes. Add the vinegar and raisins and cook until the sauce thickens very slightly, about 3 minutes more.
Add 2 cups of the chicken broth, the chicken, and the vegetables and cook again over low heat for about 5 minutes. Adjust the salt. Five minutes before serving, add the fried plantain and just heat through.