Season the pork shoulder with salt and pepper. Place it in the slow cooker.
In a bowl, mix buffalo sauce, chicken broth, garlic, onion, and apple cider vinegar. Pour over the pork.
Cover and cook on low for 8-10 hours or on high for 5-6 hours, until the pork is tender.
Remove the pork and shred it with two forks. Strain the cooking liquid and mix it with melted butter and extra buffalo sauce.
Toss the shredded pork in the sauce until well-coated. Serve on buns, tacos, or salads.