Dump the Frank's Hot Sauce directly into the slow cooker.
Mix in the Ranch packet mix and whisk/stir until mostly dissolved.
Add the butter, and finally, the boneless chicken breasts.
Cover the slow cooker, set on high, and cook for approx. 5-6 hours. If you're going to be away for over 6 hours, you can set the slow cooker to low and cook for 6-8 hours.
Approx. half hour before serving time, shred the chicken into fine shreds with two forks and stir. Cover and allow to sit for 30 minutes.
Serve on fresh buns!