Is it Possible to Breed for a Different Sex Ratio?

[Jazzin]

I've heard that some hens do not lay eggs with a 50/50 sex ratio...is this true and is it possible to breed for hens that lay more eggs containing pullets than cockerels? Does anyone have experience with this?

 

[GodLovesU]

I don’t think so…..

 

[Sally PB]

If it were, commercial poultry operations would be all over it. The fact that they aren't doing this means that it's not.

 

[LaFleche]

I've heard that some hens do not lay eggs with a 50/50 sex ratio...is this true and is it possible to breed for hens that lay more eggs containing pullets than cockerels? Does anyone have experience with this?

Stress of any kind will cause a hen to produce more male offspring.

 

[wrathsfarm]

I've got an EE who I hatched 3 from in 2023...all males. In 2024 I hatched another 3...2 males, 1 female.
I've read that some hens are prone to sway the gender balance and produce more male progeny, but I have no science-y stuff to back it up, and my hatch rates are not high enough to confirm or deny to that also.
I will be doing another batch of BCM x EE again along with the Olive Egger now here because I've been after Olive eggs and finally have one and now want more....

Maybe 3rd times the charm and we'll get all girlies. (3 seems to be her number )

 

[SourRoses]

Yes it's possible.
I had a hen who laid more females than males. I only hatched 20 from her, 4 were male. One of her daughters has so far yielded 5 with only 1 male.
The odd thing is, they're from a breed that prizes the males over the females, for the feathers (Genetic Hackles)... many breeders cull excess female chicks .

So it seems to me like nature working hard to correct an imbalance. It could be that the genes for sex ratio are epigenetically influenced.
For comparison, there are scientific studies showing the way human fertility is epigenetically influenced by hardship... people who experienced stress/hunger when young go on to produce more offspring, while content/secure people produce few, regardless of culture, religion, etc. It's part of the species drive to survive, when times are tough nature wants to solve the problems by throwing more life at it, until some of them succeed.

If it is epigenetics at work in poultry sex ratios, breeding for a lopsided ratio could potentially be reversed in time.

As for imbalance with the male ratio, especially when males are in excess of 50%, that's more likely to be incubation conditions. Because males have 2 copies of more genes than females, they are genetically more resilient to stress on the body (in humans, this is reversed, it's women who have more doubled genes therefore more resilience against some ailments). Therefore, an incubation with excessive heat will harm more females than males and throw off the sex ratios.

The reason hatcheries/industry don't pursue this, is likely the cost-benefit analysis. A lower percentage of male chicks still leaves them dealing with male chicks - they still have to hire the professional sexer (fly them in) and everything else.
After the cost for generations of breeding to get a minimal change, it's not going to be worth it to them.

 

[Jazzin]

Thank you all for the responses! I wasn't aware that environmental factors could have an effect on the ratio, so I did some searching and found a study in which environmental factors were considered. Apparently higher-stress environments cause many wild bird species to produce more females, but strangely enough when hens were treated with stress hormones before laying they instead produced WAY more males. To my current understanding the ratio is influenced more by the environment of the birds and then influenced to a smaller degree by genetics.

 

[Shadrach]

I believe given enough time the ratio of males to females will balance out at 50/50.