Place chicken breasts in the bowl of a slow cooker.
Top with honey and brown sugar.
Sprinkle seasonings; cayenne pepper, garlic salt, smoked paprika, and red pepper flakes over the top of the chicken.
Drizzle with vinegar and top with pats of butter.
Cover and cook on low for 8 hours.
Remove chicken breasts and shred with a fork.
Return shredded chicken to the slow cooker and stir with the juices in the bottom of the slow cooker. Cover and cook while you prepare the buns.
Spread mayonnaise onto each bun and add a sprinkle of garlic salt.
Toast in a skillet until lightly browned.
To serve, top toasted buns with shredded chicken, some coleslaw and sliced pickles if desired.