Objective of the current study is to estimate nutrient requirement of Tàu Vàng broilers based on commercial feed of GreenFeed Viet Nam Join Stock Company and replacement of water hyacinth aiming at reduction of feed cost in poultry production. A completely randomized design with five treatments and six replicates, in which each replicate contained 4 cocks or 4 hens, was used. Tàu Vàng chickens at 6-11 weeks of age in the treatments were fed ad libitum/ restricted (70 or 80% of the ad libitum intake) commercial diets with supplementation/no supplementation of water hyacinth. As a result, supplementation of water hyacinth was most effective when broilers were added (i) ad libitum intake of commercial feed at 6-8 weeks old of the growing stage or (ii) restricted intake of commercial feed during the stage of 6-11 weeks old.