One hundred and twenty two, one day old male Ross broiler chicks were used to evaluate the effect of Salkil, Prefect (two commercial feed additives) and Flavomycin (Antimicrobial growth promoter) on performance and on intestinal microflora. The chicks were divided into six groups: a) control with no additives, b) as control group but supplemented with 4 kg/ton Salkil during the whole period of the experiment (42 days), c) as control group but supplemented with 4 kg/ton Salkil during starting period and 2 kg/ton Salkil during the rest of the experiment, d) as control group but supplemented with 3 kg/ton Prefect during the whole period of the experiment, e) as control group but supplemented with 3 kg/ton Prefect during starting period and 2 kg/ton in the rest of the experiment (42 days) and f) as control group but supplemented with 125 g /ton Flavomycin during the whole period of the experiment. Another trial was performed to evaluate these compounds as feed preservatives by storage of feed supplemented with the examined compounds. Samples were collected biweekly intervals up to 8 weeks. Results revealed that no significant effect was noticed with the addition of Salkil or Prefect on body weight gain of broiler chicks or feed efficiency compared to the control group, but there was a numerical improvement in broiler performance in group C. An increase in the count of caecal lactic acid bacteria in group C and D indicated that the supplementation of feed with the conditions followed in these two groups has an acidifying effect in the intestine of the treated chicks. As feed preservative, the best results were obtained by supplementation of feed with 3 km/ton of Prefect.