In a large pot with a tight-fitting lid, add 2 cups of water and chicken stock. Add turkey leg and heat over medium heat and cook for 30 minutes until the liquid is a golden color and has been imparted with the turkey leg’s flavor.
Meanwhile, thoroughly clean greens in a sink full of warm water. Pull the leaves from the stems. Combine the leaves in small stacks, then roll them like a cigar and cut the crosswise into 1 inch wide pieces, leaving you with strips of leaves. Discard the stems.
To the pot, add the diced onion, bell pepper, turnip, half of the greens and all the oil. Cover with lid and allow first batch to cook down for ten minutes. The greens will reduce down by half.
Stir in seasoning salt, paprika, Worcestershire sauce, vinegar, brown sugar, red pepper flakes and remaining greens.
Stir consistently, making sure to break up any packed greens and turn the lighter, less cooked greens to the bottom. Cook until greens are slick and tender, about 50-55 minutes. You may need to add more water to the cooking liquid; you want the greens to braise, not fry (this will help create a delicious pot likker).
Most of the meat will have fallen off the bone, but shred any remaining large pieces and stir back into the greens and serve.