Thanks to Dr. Bakri for his remarks about stress factors.
In hot and humid climate, one of the fundamental stress factor is the management of house inner climate. Grown broilers produce high level of enthalpy (heat content) inside the house. One of the best system to overcome the heat stress is the tunnel ventilation design. But in our region, few farmers use such system. That's why the inability of house climate control is the major cause of high mortality, provided the other variables are under strict control ( feed, biosecurity measures and medical program etc..etc..).