Poach the drumsticks
In a large (8-quart) Dutch oven or other heavy-duty pot, combine the broth, onions, garlic, and spices. Add the drumsticks and bring to a boil over medium-high heat. Reduce the heat to a simmer, cover the pot, and cook until the meat is tender, about 1-1/2 hours. During cooking, add broth as needed to keep the drumsticks submerged, and turn them over from time to time. Transfer the drumsticks to a rimmed baking sheet and let cool. Strain the broth and save. Discard any solids.
When the legs are cool enough to handle, remove the skin and discard. Pull the meat from the bones and remove any sinews. Leave the meat in the largest chunks possible and set aside in a large bowl.
Make the mole sauce
Tear the chiles into large pieces, discarding the stems and seeds.
In a large (12-inch), dry, heavy-duty skillet over medium-high heat, toast the chiles, turning them frequently, for 10 to 15 seconds. Transfer the chiles to a bowl, add the raisins, cover with 3 cups boiling water, and soak for at least 30 minutes or until soft.
Drain the chiles and raisins. Set aside 1/2 cup of the soaking liquid and combine the remaining liquid with the turkey broth.
Put the almonds and chocolate in a food processor and pulse several times to finely grind them. Add the chiles and raisins, the reserved 1/2 cup of chile liquid, and the tomatoes, tortillas, onion, garlic, oregano, cumin, fennel, allspice, cinnamon, and cloves. Process until smooth.
In a large (8-quart) Dutch oven or other heavy-duty pot, heat the oil over medium heat. Add the chile mixture and cook, stirring frequently, until it darkens and becomes quite thick, about 8 minutes. Add 4 cups of the turkey broth and season with a pinch of salt and pepper. Cover, reduce the heat to maintain a gentle simmer, and cook until the sauce is thick but still pourable, about 40 minutes. Add more turkey broth if it becomes too thick.
Stir in the turkey meat and cook for 10 minutes over low heat so the turkey can absorb the flavors of the mole sauce. Season to taste with salt and pepper. Spoon the turkey and sauce into a shallow serving bowl and sprinkle with the toasted sesame seeds.
The turkey legs can be poached a day ahead (refrigerate the meat and broth separately). The chiles and raisins may be soaked overnight and refrigerated in the soaking liquid.