In a large bowl, combine the ground chicken, breadcrumbs, eggs, salt and pepper. Mix thoroughly to ensure ingredients are evenly distributed.
Using about 1 tablespoon of the chicken mixture, lightly flatten out into a disk and add a piece of blue cheese (about ½ inch piece.) Close the chicken around the cheese and roll into a ball. Cheese should be completely encased by the chicken so it will not leak through into the sauce while cooking.*
Repeat the chicken, cheese, rolling process until all the chicken is used.
In a crock pot, add ½ cup of hot sauce to the bottom to prevent meatballs from sticking or burning. Layer meatballs and add the remaining 2 cups of hot sauce so the meatballs are evenly coated.
Scatter pieces over butter over the top of the meatballs. Cover and cook on high for two hours.
After cooking, gently stir meatballs to evenly coat with hot sauce and to stir in any separated butter. Transfer to a serving dish and coat with remaining buffalo sauce from the crock pot.
Sprinkle the buffalo chicken meatballs with chopped celery. Serve alongside blue cheese or ranch dressing for dipping.