6Baker D H, Han Y. The Papers of the 82nd Annual Meeting of the Poultry Science association. 1993, 7:26 - 29.
7Lopez G, Leeson S. Response of Boiler Breeders to Low Protein Diets I Adult Breeder Performance. Ponltry Science, 1995,74:685-695.
8A Meluzzi, F Sirri N. Tallarico and A Franchini Nitrogen Retention and Performance Brown Laying Hens on Diets with Different Protein Content and Constant Concentration of Amino Acid and Energy. British Poulrty Science, 2001, 42: 213-217.