Moreover, the immune system of heat-stressed poultry may be affected.The immune organs of chicks at different ages submitted to heat stress of displayed significant atrophy and edema, necrosis of bursa cells and reduced both cell-mediated and humoral immunity ().The duration of each behavior by each individual bird was recorded using a stopwatch, and their mean weekly values were calculated.Changes in the duration of behaviors in response to heat stress of the experimental groups were calculated.
At 8 days of age, the chicks of PHS subgroups were submitted to heat stress (40C daily).
Therefore, poultry production suffers huge losses due to heat stress, which is caused by high temperatures in many areas during the summer.
According to a recent report, the damage caused by heat stress in poultry resulted losses of up to USD 0.728 billion in five states in the USA, including California ().
ABSTRACT One-day old chicks were randomly distributed into acute heat stress (AHS) or persistent heat stress (PHS) groups.
Each group was further divided into control (CK), and three AHS ages (1, 2,or 3 weeks of age) experimental subgroups.