Typical conditions leading to heat stress occur where environmental temperatures are 25 degrees C (77 degrees F) or more, and relative humidity is greater than 50%.
Map of discomfort zones
If you live in an area on the map shaded in red then heat stress is a year round problem. If you live in the area shaded in pink then heat stress is a problem for some part of the year.
Because most farmers who live in hot and humid climates have not experienced animals and poultry production levels in cool climates, they do not realise how much improvement in productivity is possible.