Place the chicken breasts into the slow cooker.
Sprinkle the Ranch dressing mix over the chicken; add the Frank’s Red Hot, butter, and vinegar.
Cook on low for 4-6 hours, or until the chicken reaches an internal temperature of 165º F.
Once the chicken is cooked, pull it apart with two forks until all of the chicken is shredded. Give everything a good stir, then cover and let it cook for another 20-30 minutes.
Serve the chicken on buns with diced celery and blue cheese crumbles or dressing.