The minimum for buffet is about 20 pounds per 100, not very meaty, assumes additional veggies, 25 per 100 is richer. 4 gallons of sauce/gravy, with about 4 pounds of celery, 1 1/2 pounds each onion and bell pepper, 1 pound canned drained pimento is a typical minimum. Some half and half in the sauce is very tasty.

Also assumes 2 not too giant biscuits for each serving.

This will be rather similar to the sausage gravy recipe on the site:
www.ellenskitchen.com/bigpots/sausage.html

Use butter (or part schmaltz/ chicken fat) instead of the natural grease of the pork. You can use part chicken broth for the liquid. The chicken could be poached in broth, then either shredded or cubed.

Chopped parsley for garnish?