9Lopez G, Leeson S. Response of Boiler Breeders to Low Protein Diets I Adult Breeder Performance. Ponltry Science, 1995,74:685-695.
10A 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.