This work aimed to enhance the resistance of cocks against hot climate by using both early heat shock exposures (HSE) and glutamine injections (GI). Eight hundred one-day old of male Sinia chicks were randomly divided into eight groups to investigate the effect of (HSE) and (GI) on some physiological parameters, immune responses and semen quality during reproductive period under heat stress conditions. The 1st group of chicks served as a control that reared under natural conditions. The 2nd group of chicks was managed thermally like the control group during growth period, while through reproductive period the cocks were exposed to heat challenge (38 ±1ºC for four hours from 12:00 till 16:00 for one day) at 24, 30 and 34 weeks of age. The 3rd group (HSE1) was exposed to early heat shock (41 ±1ºC for four hours from 12:00 till 16:00 for 3 consecutive days) at age of 3 days similarly, the 4th group (HSE2) received the same early heat stress, in addition to GI (0.75 mg/kg weight intra peritoneal injection) at age of two days. The 5th group (HSE3) was exposed to heat shock (41 ±1ºC for four hours from 12:00 till 16:00 for 3 consecutive days) at age of 3 days and 35 days. Also, 6th group of chicks (HSE4) received heat shock two times (at age of 3 and 35 days) and two GI (0.75 mg/kg weight intra peritoneal injection) at 2 and 34 days of age. Three times of heat shock (41 ±1ºC for four hours from 12:00 till 16:00 for 3 consecutive days) were applied to chicks of 7th group (HSE5) at 3, 35 and 112 days of age. Similar schedule of heat shock was applied to 8th group (HSE6) that received also, three times of GI (0.75 mg/kg weight intra peritoneal injection) at 2, 34 and 111 days of age. During reproductive period, HSE1, HSE2, HSE3, HSE4, HSE5 and HSE6 groups were reared under natural conditions and they were exposed to heat challenge at 24, 30 and 34 weeks of age (similar to that applied for the second group. 38 ±1ºC for four hours from 12:00 till 16:00 for one day). Cocks of 8th group (HSE6) expressed the best level (P<0.05) of heat shock protien70 (HSP70) as well as all other measured parameters compared to control and other groups.