The aim of the study was to analyze how application of per os licorice extract (LE)(Glycyrrhiza glabra) and colloidal nano silver (CNS) affect the performance status of ross broiler chickens in both embryonic and growth period. In Embryonic period Eight hundred Fertilized commercial eggs were randomly assigned to one of 10 treatments with five replicates (20 eggs each replicate). This experiment was arranged based on a completely randomized design (CRD). First group was control (without injection), second group was control (0.1 cc injection of Sterilized distilled water) and groups from third to ten were included 0.1 cc injection both LE in three levels (0, 100 and 200 ppm) and CNS in three (0, 30 and 60 ppm), in form of alone and combination with each other. For Growing period after hatch, the best treatments in first step were choosed and transferred to this step. Treatments consisted of two control groups from first step and other group treated in diet with both LE in three levels (0, 1 and 2 gr/kg) and CNS in two levels (0 and 120 ppm) in form of alone or combination with each other and a group treated with antiobiotic.Injection of 60 ppm CNS and 100 ppm LE increased significantly hatchability percent in comparison other treatments(p<0/05). The chicks body weight and length after hatch was increased significantly in all treatment (especially in treatment with the highest levels of CNS and LE) than two control groups(p<0/05). There was a significant difference between 450 mg/kg Antibiotic and control group with other treatments(P<0.05). The highest FCR occurred by these treatments. There wasn't any difference between treatment consist of CNS and LE. But the chickens treated with 120 mg/kg CNS and 2gr/kg LE+ 120 mg/kg CNS had the lowest FCR. Production index significantly affected by treatments(P<.05). The chickens consumed 120 mg/kg CNS and 2gr/kg LE+ 120 mg/kg CNS compared to chickens treated with 450 mg/kg Antibiotic showed the highest Production index. Inovo a
