This study was conducted to evaluate the impact of short and long-term 
thermal manipulation during early embryogenesis (E4-6d) on the productive 
performance of quails. A total of 600 quail eggs were divided into 4 equal 
groups (4 groups × 5 replicates × 30 eggs). In the first group (control), eggs 
were incubated at 37.5 °C & 55–60% RH from day 0 up to 14 days of 
incubation. In the second group (short thermal manipulation/ STM), eggs 
were daily exposed to 39.0 °C and 55-60% for three successive days (4-6 d) 
during early embryogenesis for 3 hours. In the third (middle thermal 
manipulation/MSM), eggs were daily exposed to 39.0 °C and 55-60% for 3 
successive days (4-6 d) during early embryogenesis for 6 hours. In the fourth 
(long thermal manipulation/LSM), eggs were daily exposed to 39.0 °C and 
55-60% for 3 successive days (4-6 d) during early embryogenesis for 12 
hours.
The achieved findings could be summarized as follows:
• The body weight at 35 and 42 days of age for chicks produced from eggs 
in the 4th group was significantly decreased compared with those of the 1st 
(control), 2nd (STM), and 3rd (MSM) groups.
• The obtained results showed that the daily and total weight gain during 
(28–24 d) and (1–42 d) for chicks produced from eggs in the 4th group) were 
significantly decreased compared with those in the 1st (control), 2nd (STM), 
and 3rd (MTM) groups.
• The daily feed consumption for quail chicks in the 4th group during 1–14, 
14–28, and 28–42 days of age was insignificantly decreased as compared 
with those in the 1st (control), 2nd (STM), and 3rd (MTM) groups.
• The total feed intake for quail chicks in the 4th (LTM) group during 1-42 
days of age was significantly decreased as compared with those in the 1st 
(control), 2nd (STM), and 3rd (MTM) groups.
• The obtained results showed that the daily and total feed conversion ratios 
in different groups were insignificantly influenced.
It is suggested that short (3 hours/d) and middle (6 hours/d) thermal 
manipulations be utilized due to their beneficial impact on the growth of 
quail birds during the growing period.