Separate beans, place into a large container, and cover with several inches of cool water. Let beans soak 8 hours to overnight.
Heat butter in a skillet over medium-high heat. Saute onion, bell pepper, jalapeno, and garlic in the hot pan until soft, 5 to 7 minutes. Remove from heat.
Place turkey carcass into a slow cooker with drained beans, sauteed vegetables, chicken broth, 3 tablespoons chili powder, and bay leaves. Cover and cook on Low for 8 hours.
Remove any bones from the carcass and add tomatoes, corn, masa, hot sauce, chili powder, white pepper, red pepper flakes, and salt to taste. Let simmer on Low for another 30 minutes.