Dr. Jessica D. Starkey of Auburn University recently reported on the effect of incubation temperature during the 4-to-11-day period. The project, funded by the USPOULTRY Foundation as Project No. 725, compared a suboptimal temperature of 36.1C with a high temperature of 38.6C and a conventional temperature of 37.1C as a control. It is known that muscle fiber and satellite cell populations are influenced by early incubation temperature.
The results of the study demonstrated that irrespective of temperature, there were no differences in embryonic mortality, but hatch-of-fertile eggs was higher in the control group compared to either cold or hot treatments. Chicks from eggs subjected to early cold temperature were heaviest at hatch compared to the chicks from eggs subjected to high temperature during early-stage incubation with a negative difference of ten percent.
Cold incubation impacted final body weight in addition to suppressing breast, wing, thigh and drum yield compared to controls. Breast weight was reduced by 25g, or six percent compared to control and high-temperature incubation treatments. Temperature did not affect the incidence of pectoral myodegeneration (wooden breast or white striping).
An important consideration from the study was the financial impact of low incubation temperature during the 4-to-11-day period. The Auburn University team determined that a 1.25 million broiler per week complex would lose $7 million annually as a result of suboptimal early incubation. By extension, a 1C lower early incubation period could cost the U.S. broiler industry as much as $850 million annually.