Debone the chickens, remove the skin if desired, trim any excess fat, and place the chicken and bones in a large stockpot.
Wash and roughly chop the carrots, celery, onions, bell peppers, cilantro, culantro, and garlic. Add them to the pot.
Add the water, oregano, black pepper, bay leaves, cumin seeds, thyme, basil, and rosemary. Stir, bring to a gentle simmer, and cook for about 1 hour.
Skim off the foam and excess fat that rises to the surface during cooking.
Remove the chicken from the broth and let it cool slightly. Separate the meat from the bones and set the meat aside for other recipes. Return the bones to the pot and continue simmering for about 1 more hour, skimming any additional fat as needed.
Add the cilantro and culantro. If desired, adjust the herbs that may have been removed while skimming the broth.
Remove the bones and strain the broth through a large colander. Once the vegetables are cool enough to handle, squeeze them to extract as much liquid as possible before discarding them.
For a clearer broth, strain it one more time through a cheesecloth (optional).
Let the broth cool completely, then freeze or pressure can using your preferred preservation method.