US Poultry & Egg Association has completed a funded research project at the University of Georgia on modifying the offspring sex ratio in white leghorn chickens.
The project, Hormonal Manipulation of Offspring Sex Ratio in White Leghorn Chickens, lead by Dr. Kristen Navara is part of the Association’s comprehensive research program encompassing all phases of poultry and egg production and processing.
Research was conducted to identify possible treatments that stimulate hens to skew sex ratios to produce more females than males in commercial layers. Initial studies using progesterone were unsuccessful, since it interrupted the laying cycle in 77% of injected hens. As an alternative, the stress hormone corticosterone was injected in laying hens to determine if this treatment would alter the sex ratio of hatched chicks.
Treatment of hens with high doses of corticosterone five hours prior to lay resulted in the production of 83% male chicks, which was the opposite of expected results. Injections did not have an adverse effect on egg production or fertility. Although the results of this research did not produce the desired results of more female chicks, there was evidence that corticosterone may increase the ratio of male chicks.