The U.S. Department of Agriculture National Organic Program currently permits a small amount of synthetic MET in feeds for organic poultry production, but has been reducing its use since the establishment of the program in 2002. Currently, 0.9 kg of synthetic MET per 907 kg of feed is permitted for laying and broiler chickens, averaged over the life of the flock [5]. Synthetic MET is typically used in commercial poultry diets in the U.S., both conventional and organic, and is provided in the form of DL-methionine or 2-hydroxy-4(methylthio) butanoic acid (hydroxyl analogue free acid) [6].