evaluation of relation between air velocity and broiler farms production

evaporative cooling system and high air velocity management are important tools in alleviating the effects of heat stress on broilers performance during hot weather. in this study, technical and economical aspects of ventilation in varamin township broiler farms during summer were investigated. data were obtained from completed questionnaires through 20 broiler houses. information of air velocity rate, temperature, humidity of houses was measured. for economical evaluation, benefit cost ratio (bcr) and for the desired relationship between continuous variables, pearson correlation test was used. results of this study showed that bcr of broiler farms was 0.91 indicating broiler production in the continent is not economically justified. there was significant positive correlation between air velocity and production factors including production index (p<0.01), daily weight gain (p<0.01) and final body weight (p<0.05) and negative correlation with feed coversion ratio (p<0.01), mortalty (p<0.01) and total production cost (p<0.05). our study showed that 90% of houses in varamin township had less than 1 m/s air speed and did not have optimum air velocity for maximum performance and there is a potential to increase performance and production efficiency by improving ventilation system and house air velocity.