Place chicken in slow cooker. Pour buffalo wing sauce over the chicken. Sprinkle half the package of Ranch dressing mix over all and stir well, turning chicken at the same time to coat. Cover and cook on low for five hours.
Remove chicken and shred then put back in the pot for an additional 2 hours. (if you're at home) If not at home, cook for 7 hours and shred before serving. Once chicken is done, stir in 2 tbsp. butter until melted.
Load the saucy pulled chicken onto hoagie or other crusty buns and top with more Buffalo chicken sauce and ranch or blue cheese dressing on the side.