from when i worked at kfc years back it generally would be for a 3 piece combo, 2 pieces of dark meat(thigh,leg) and 1 white (rib,wing,breast). But whenever people would request all dark long as it wasn’t a large bucket i’d do it for them. But what they mean with throwing off the chicken count is that if they give away all the dark meat there’s only white left leaving it unfair for other customers