Laying
hens were allotted into 4 groups (11000 hens per each
house). The laying hens were fed with a basal diet
containing 17% crude protein and other nutrients
according to the requirements (NRC, 1994). The
ingredient composition and chemical analysis of the
basal diets (BD) are presented in Table, 1. The applied
experimental design is presented in Table 2. All the
experimental diets as well as fresh water were
constantly available throughout the experimental period
(16 weeks)