Temperature humidity index for growing tom turkeys
Temperature-humidity effects on physiological responses of tom turkeys were investigated using a twodimensional 
rotatable central composite design. Eight temperature-humidity combinations were evaluated from 23 to 
40°C and 40 to 90% RH. Response surfaces for mean, variation, and slope of core body temperature, CO2 production, 
and moisture production were used to assess level of stress at each of four ages. Temperature and humidity were 
approximately equal in their effects on physiological responses of 6-wk-old turkeys. Above 10 weeks of age, temperature 
decreased in relative significance as a stressor, and humidity appeared to be a more important factor in the birds’ ability 
to maintain homeothermy.