Remove the pork from its package and place in the bottom of a 6 quart or larger slow cooker.
In a small bowl stir together the oregano, cumin, chili powder, salt, pepper, paprika, and cinnamon.
Season the pork evenly on all sides, rubbing the spice mixture into the meat.
Cut the oranges and limes in half and squeeze the juice out evenly over the meat.
Pour in the broth, and sprinkle in the onion and garlic.
Cover and cook on low for 8-10 hours until tender.
Once the meat is tender, preheat your oven broiler to high.
Shred the meat onto a large baking sheet and spread out in an even layer. Pour 1/2 cup of the juice from the slow cooker over the meat. Broil for 8-10 minutes until crisp. Drizzle with 1/4 -1/2 cup more of the juices if desired.