There is a growing market in the U.S. for broilers in 7 ½ to 8 ½ pound range. Though there are many challenges producing such a large broiler minimizing heat stress related problems is often placed at the top of the list. Obviously to grow such a large bird the house will need to be tunnel-ventilated, but how much wind speed should the house be designed for? A number of studies conducted at the USDA Poultry Research Laboratory at Mississippi State have found significant improvements in weight ...and feed conversion efficiency for broilers grown during hot weather with an air speed 600 ft/min when compared to those grown 400 ft/min. Many poultry companies growing large boilers have confirmed the results of these studies finding relatively minimal heat stress related problems in their tunnel houses that had air speeds in the 600 ft/min range. So the question often becomes that if 600 ft/min is better than 400 ft/min, wouldn’t 650 ft/min or even 750 ft/min produce even better results?