Prepare the Meat Base: In a large stockpot over high heat, combine the water and turkey necks and bring to a rolling boil. Once boiling, reduce to a low boil, cover the pot, and let it cook for 2 hours. This creates a rich, flavorful base as the smoky flavors release into the broth.
Add Aromatics: After 2 hours, check the water level and add more if needed to just cover the necks. Add the chopped onion, garlic, and bouillon powder, stirring to combine everything. Taste the broth and adjust with seasoning salt if needed. The liquid should be flavorful and slightly salty at this point.
Cook Vegetables: Add the quartered potatoes and prepared string beans to the pot. Cover again and continue cooking at a low boil until the potatoes become quite tender and the beans soften completely, approximately 45 minutes. The vegetables will absorb the smoky flavors from the broth.
Season and Finish: Add the ground black pepper and stir to incorporate. Taste again and adjust seasonings if necessary. Remove the pot from heat but keep it covered to maintain temperature.
Prepare the Meat: Remove the turkey necks from the broth and set aside until cool enough to handle. Once cooled slightly, pull the meat from the necks, discarding the skin and bones, then return the meat to the broth. If using ham hocks, either break them up directly in the pot with a cooking spoon or remove them to pull off the meat, then return the meat to the pot.
Serve: Ladle the beans and potatoes into bowls, including some of the flavorful broth and meat pieces for a complete serving.