This experiment was conducted to study the effect of prebiotic, probiotic, short chain fatty acid, organic acid, and essential oil as growth promoters on performance, economic efficiency, cecal microbial count and nutrients digestibility of broiler chickens. A total number of One hundred and eighty Unsexed broiler chickens (Arbor Acres) at 7 days of age were randomly distributed into sex treatments, each in 6 replicates , with 5 bird chicks per replicate Basal diets were supplemented with 0 control , 1st Biacid 0.5%, 2nd Valeric Acid 1.5% , 3rd Citric Acid 0.5% , 4th Fructo oligosaccharides (FOS)1% , 5th probiotic (bacillus subtilis 1* 1012) 0.75% .Diets were fed during starter (7-21d) and grower (22-39d)of age and offered to bird ad libitum with free access to water up to 39 d of age, Nutrients digestibility were determined for all experimental treatments . Chicks fed diet either with Fructo oligosaccharides (prebiotic) or Valeric acid had significantly (P<0.05) greater production performance, Economic efficiency, European Production Efficiency Factor and increased the number of beneficial Lactobacillus than the control group. Both Valeric acid,and Fructo oligosaccharides also, had significantly (P<0.05) improved the digestibility of crude protein, ether extract, dry matter and crude fiber. In conclusion, the use of FOS at 1% as well as Valeric acid at 1.5% are considered beneficial growth promoters for broiler chicks under Egyptian summer conditions.