. Chicken productivity is not only determined by body weight increase and feed efficiency but also disease resistance. Avian influenza (AI) is still an endemic in Indonesia. Highly mutative characteristic of AI causes unsuccessful vaccination to preventing chicken mortality; therefore, feed modulation alternatives are sought to raise body weight and body immune as well. Virgin coconut oil (VCO) contains fatty acid potential as antimicrobe and antivirus; VCO intake is therefore expected to increase chicken body immune. This research aimed at feed modulation to increase broiler chicken productivity. Forty broiler chicken of one day old (DOC) were used and the research applied Completely Randomized Factorial Design in which factor one was two vaccine levels namely AI-vaccinated chickens and AI-unvaccinated chickens. Factor two used four levels of VCO: 0, 5, 10, 15 mL/kg feed. DOC chickens were divided into eight treatment groups and repeated in five experiment units. Feed and water were given ad libitum. The result demonstrated that in spite of heterophile increase in AI-vaccinated VCO-given chickens, heterophile/lymphocyte ratio and feed intake were not significantly different among all treatment groups. With the highest body weight found in AI-vaccinated chickens given 10ml/kg feed VCO, it could therefore be concluded that VCO intake of 10mL/kg feed could raise body weight
