Selenium is an indispensable component for fattening broiler chickens of meat productivity. It normalizes their growth and metabolism by participating in the redox transformations of glutathione. The goal of this work was to examine the possibility of using a drug based on selenium nanoparticles and the "Ekstraselen+Vit" vitamins in the diet of broiler chickens. It is experimentally proved that supplementing the diet of poultry with a feed preventative additive leads to higher growth rates and lower mortality rates of young poultry, lower feed costs per unit of yield. During a scientific and economic experiment, we determined that there was an increase in the pre-slaughter weight, slaughter yield and the yield of certain carcass parts in accordance with anatomical butchering. Data on blood haematological parameters of broiler chickens is presented. We identified the improved chemical composition and functional-technological properties of raw meat, produced from broiler chickens, grown with the use of "Ekstraselen+Vit". The concentrations of selenium in the poultry processing products were determined. It was found that the use of the feed additive in the diet, based on selenium nanoparticles, contributes to the accumulation of this element in broiler chickens bodies. It is feasible to use enriched meat to produce medical and preventative food.