Step 1

Place the chicken, leek, tomatoes and their juices, carrots, celery, garlic, bay leaf, and 1 teaspoon salt in the insert of a large slow cooker (at least 4 quarts). Season with pepper and add the broth and water. Cover and cook on low for 6 hours or high for 4 hours. Meanwhile, prep the other vegetables and cook the pasta.

Step 2

Cook the pasta shells according to package directions. Drain and rinse in cold water, then store in the refrigerator.

Step 3

Remove the stems from the chard. Cut the leaves crosswise into 1-inch-wide pieces. Place in a large bowl. Core the cabbage, thinly slice, and add to the bowl of chard. Halve the zucchini lengthwise, then cut crosswise into 1/4-inch pieces and add to the bowl. Refrigerate until the broth is ready. (The pasta can be cooked and the vegetables prepared up to a day in advance.)

Step 4

When the broth is ready, remove the chicken and bay leaf to a plate and let cool slightly. Meanwhile, add the bowl of vegetables to the broth and stir to combine. Cover the slow cooker, turn the heat to high if not already on high, and cook until the greens are tender but not mushy, 20 to 30 minutes.

Step 5

Remove the chicken meat from the bones and discard the skin, bones, and bay leaf. Shred the meat into bite-sized pieces. Stir the garbanzos, chicken, and cooked pasta into the soup. Taste and season with salt and pepper as needed.