Limited research suggests the effect of brown seaweed in animal nutrition for improving gut health and performance, but there isn't any research suggests the effect of oral liquid seaweeds brown algae in broiler nutrition. So, this study was aimed to evaluate the effect of liquid brown seaweed algae (Ascophyllum nodosum) supplementation on broiler chick's performance and their intestine histology. The experimental chicks (total number of 120, one - day old, Indian River chicks) were used and fed the same diets during the experimental period (1–35 days).  Brown seaweed algae were added in fresh water at the concentrations of 0 and 1 ml/ liter fresh water.  Results indicated that chicks received 1 ml liquid brown algae/1 liter of drinking fresh water had the greatest body weight gain, better feed conversion ratio, significant increases in total protein, albumin, and globulin and significantly decreases in total lipids and total cholesterol than that in the control chicks. On the other hands, water consumption and relative weight of carcass were not significantly affected by the algae supplementation. Histological observations concluded that birds, which received brown algae in drinking fresh water, had better intestinal health in terms of well-developed villi with their columnar epithelial lining, which indicative of an increase of the digestive and absorptive surface area leading to better nutrient utilization. These results suggested that liquid brown algae have a beneficial effects on the growth performance, intestinal development without any side effects and we can replace it with powder brown algae in broiler chicks, but we need more researches to confirm this item.