DESCRIPTION OF PROBLEM
Per-capita consumption of broiler and poultry meat products increased from 18.3 kg (40.2 lb) in 1970 to 39.3 kg (86.5 lb) in 2007 [1]. This dramatic increase in per-capita consumption led to broiler products surpassing pork in 1986 and beef in 1993 to become the most consumed meat product in the United States [1]. Feed efficiency also increased significantly during the same period. In 1944, broiler chickens required approximately 4.1 kg (9 lb) of feed for each 1 kg (2.2 lb) of BW gain. By 1994, broilers required only 1.8 kg (4 lb) of feed to produce 1 kg (2.2 lb) of BW gain [2]. The broiler industry has become more efficient at producing meat by using less feed to grow birds in a shorter amount of time. It is a remarkable feat of agricultural technology that the broiler industry can produce a 2-kg bird using 3.6 kg of feed in 6 wk [3]. The reduction in the market age of the broiler is also significant because as the broiler ages, more feed is directed toward maintenance rather than adding BW to the broiler.