An experiment was conducted to compare the effects of different levels of Artemisia sieberi with a chemical anticoccidial drug (Diclazuril) on control of coccidiosis, body weight and feed efficiency of male broiler chicks. Three hundred day-old male broiler chicks were randomly divided to four treatment groups of three replicates. Each replicate allocated in separated floor pen. Treatment one fed diet without any anti-coccidial supplements as control group. For feeding the chicks in other treatments 1.0 and 2.0 % of Artemisia sieberi, and 200 ppm Diclazuril, were used respectively. Chickens in all of the treatments were challenged orally by a mixture of oocystes of four pathogenic species of Eimeria (including E. acervulina. F. tenella, E. maxima. And F. necatrix) at the end of third week of age. Flock was daily monitored for signs of disease and mortality. Fecal samples were collected and oocyst per gram of feces (OPG) determined. Body weight (BW), feed intake (Fl), and feed conversion ratio (FCR) were determined at the end of 3,6 and 7 weeks of age. Results showed that the OPG in control group was significantly more than the other three groups (P<0.01), during the entire period of 6 to it days of post-challenge. Chicks fed diet supplemented with 200 ppm Diclazuril had OPG significantly lower than chicks which were received 1.0% and 2.0 % A. sieberi. At the end of third weeks of age, there were no significant differences among BW and FT of dietary treatments (P>0.05), but feeding chicks with diet containing 1.0 % of A. sieberi improved FCR significantly (P<0.05) in comparison with chicks received diets supplemented with 200 ppm Diclazuril or 2.0 % of A. sieberi. At the end of sixth and seventh weeks of age. Diclazuril treated group increased BW significantly (P<0.05) compared with control. Supplementation diets with 1 .0 and 2.0 % of A. sieberi or 200ppm Diclazuril did not affect Fl and FCR significantly.
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