and could meter and feed 16 dry microingredients and an almost unlimited number of liquid ingredients. Abel (1992) estimated that better than half of full line feed plants and a majority of the poultry integrators are using some type of micreingredient system. Although nearly every new facility includes a microingredient addition system in the design, there is also considerable activity in retrofitting such systems into existing plants. Some feed manufactures have designed and fabricated their own microingredient systems (Rueckert, 1984).