Incubation temperature does not influence sex ratio in meat-type chickens

Summary

Slight changes in incubation temperature of meat-type chickens reduced the hatch rate and did not change the natural female to male hatch rate.

Situation

If the poultry industry could choose to skew the sex of the chickens that hatch to better meet the product they sell, this could have a dramatic financial impact. Broiler companies would prefer to have mostly males because of their more efficient and rapid growth rate, while egg production companies would obviously want to maximize females for egg production. If incubation temperature could alter sex ratio in birds, this would be simple to implement and have potential global impact. When lizard and turtle eggs are incubated at high or low temperatures the sex of the hatchling can be skewed toward females or males. A few reports suggestion that this same mechanism may alter sex ratio in birds, while others think that varying the incubation temperature only causes selective mortality during incubation.

Response

Chicken eggs are routinely incubated by backyard farmers, bird fanciers and large poultry companies all over the world, and the specific incubator temperature required to maximize hatching varies by chicken variety. Meat-type chicken strains are routinely incubated between 99.8 and 99.5 F, with the most recent trend at 99.5 F. Sex ratio at hatch usually is very close to 1:1 with 50 females hatching for every 50 male chicks. To test the concept that perhaps we could sway this ratio in one direction or the other, broiler eggs were incubated at 99.5 F plus or minus 1.5 F. Incubating outside of this range did not seem practical due to slowing the entire incubation period too much with the low temperature or causing high mortality with the high temperature.

Impact

The female to male ratio at hatch was unaffected by incubation temperature in broiler chickens. The higher incubation temperature used reduced the number of eggs that hatched, by increasing embryonic mortality, but the mortality was similar for both sexes. This did not prove to be a practical method to skew the sex of meat-type chickens.

State Issue

Agricultural Profitability and Sustainability

Details

• Year: 2013
• Geographic Scope: National
• County: Clarke
• Program Areas:
  • Agriculture & Natural Resources