Table 1.

Effect of heat stress on poultry performance.

Species	Conditions	Outcome	Reference
Broiler chicken	32 °C	Excessive panting, elevated wings, ground squatting, standing, sleeping, sitting, and drinking, reduced feeding, body weight, AFI, and high FCR	[60]
Broiler chicken	30 °C	Decreased body weight, body gain weight, reduced growth hormone level, Insulin-like growth factor-1, increased cholesterol and glucose level, decreased villus height, crypt depth and villus surface area, and high FCR	[61]
Layers (Hen)	34 °C, RH 65%	Decreased feed intake, egg production, decreased villus height, crypt depth, and villus surface area High TNF-α, IL-1, IL-6, corticosterone	[45]
Layer	34 ± 2 °C	Decreased feed intake, low egg production, eggshell thickness, eggshell strength, and less egg weight	[51]
Layer (Hen)	35 °C, RH 65%	Decreased feed intake, weight gain, egg weight, and eggshell thickness	[26]
Japanese quails (12 weeks old)	35.8 ± 0.6 °C	Fertility 78.9% Hatchability 74.1% Poor eggshell quality, reduced eggshell thickness, eggshell weight, eggshell percentage	[43]
Japanese laying quail	34 °C	Feed intake decreased by 7.1% Bodyweight decreased by 7.7% Body weight gain decreased by 14.5% Egg production decreased by 23.3% Egg weight decreased by 14.3%	[62]
Egg-laying sheld duck (Tadorna ferruginea)	34 °C, RH 65%	Feed intake decreased by 11.9% Daily egg production decreased by 7.3% Egg weight decreased by 2.9% Decreased eggshell strength, eggshell thickness	[39,63]
Shanma duck Laying duck	34 ± 1 °C	Decreased feed intake, reduced egg weight, lower egg albumen height, and Haugh unit	[64]
Turkey	35 °C 35 °C	Decrease T3 (37.5%) Increase T4 (30%)	[65]