In a small nonreactive saucepan, boil down the cider almost to a syrup, about 2 to 3 tablespoons. Cool and reserve.
If using chicken thighs, coarsely grind the boned chicken and skin or chop coarsely in batches in a food processor. Add the apple cider and the remaining ingredients to the ground chicken in a large bowl or plastic tub and blend thoroughly with your hands. Fry a small patty until done and taste for salt, pepper, and other seasonings.
Divide sausage into 7 or 8 portions (each about 1/2 pound), wrap tightly in plastic wrap or aluminum foil, and refrigerate or freeze for later use. Or, if desired, stuff the sausage into casings.
Courtesy of Flying Sausages by Bruce Aidells and Denis Kelly, published by Chronicle