This study was carried out to determine the effect of dietary crude fucoidans extracted from brown algaeand brown seaweed powder supplementation on performance and bacterial count on feed additives of earlybroiler chicks. A total 180 broiler chicks were assigned to 4 treatments. Each treatment had 15 chicks with3 replications. The supplementation levels of fucoidan and brown seaweed powder in the experimental dietswere 0.5% (fucoidan), 3.0% (brown seaweed). The results obtained summarized as follows: The body weightgain and weight of chicks fed fucoidan (0.5%) was heavy compared with control. Feed efficiency of chicksfed fucoidan (0.5%) slightly improved compare with control. But also not significantly different amongtreatments. Gizzard weight, length of small intestine and weight of small intestine were not significantlydifferent among treatments. The villi height of chicks fed fucoidan (0.5%) was long compared with control.According to these data, this trial proves the fucoidan could be successfully used as the dietary supplement.