Lightly grease a 6-quart slow cooker. Keep thawed chicken refrigerated until the cooker and seasonings are ready.
Whisk 1/2 cup hot sauce, broth, garlic powder, onion powder, dill and salt in the cooker.
Turn the chicken in the sauce and arrange pieces in one even layer where possible. Cover and keep the lid closed.
Cook on LOW for 3 to 4 hours or HIGH for 2 to 3 hours, beginning temperature checks at the early end.
When every piece reaches at least 165°F, transfer chicken to a clean bowl, rest 5 minutes and shred with two forks.
Skim excess fat if needed. Return chicken with remaining 1/4 cup hot sauce and optional butter. Cover 5 minutes, then balance with vinegar if needed.