hybrid commercial chicks (Hubbard Flex) were A total of /450/ reared from 1 to 42 days of age. Chicks were distributed into five groups; each group contained 90 birds within three replicates. Five diets were used; the first was the traditional diet (control group) and the others differed in the growth promoters added and were as following: nutritional antibiotic (Lincomycin) for the second group, probiotic (Bacillus subtilis) for the third group, prebiotec (manna oligosaccharide) for the forth group and finally a mixture of organic acids for the fifth group.