Fill a medium-sized pot halfway with water and bring to a boil. Break the stems off of all of the dried chiles and add them to the boiling water. Let the chiles boil for 15-20 minutes until soft.
Next, drain the chiles and place them in a blender or food processor. Add the cumin, oregano, 1/4 teaspoon of salt, garlic, bay leaf, cinnamon stick, and 2 cups of chicken broth.
Blend until smooth.
Strain the sauce through a fine mesh sieve into a different container. Use a spoon to mix and push the sauce to help it through the strainer and get rid of all the seeds and any unblended pieces.
Heat oil in a small Dutch oven or pot over medium heat. Pour the sauce in the pot and bring to a boil.
Once the sauce is boiling, mix in the shredded pork. If the sauce looks too thick, add 1/4-1/2 cups of additional chicken broth. Do not add too much broth or the sauce will become too thin and runny.
Simmer over medium-low heat for 5-10 minutes until heated through and to allow the flavors to come together.
Taste and add more salt if needed.