What determines hatching gender? Any tips?

[Morelias]

I'm getting a dozen eggs shipped to me this week. This will be my 3rd time hatching shipped chicken eggs. The last 2 times I ended up with a decent hatch rate for shipped eggs, but almost ALL males, both times.

I used a different incubator each time. I read there might be some link to heat and gender formation. The first dozen was shipped in the heat and the incubator occasionally got a little warm as the room temp fluctuated so I thought ok, maybe that's the reason?

So the second dozen was shipped in winter and I got a different incubator with better temperature control. Nope, still only hatched about 1/3 females. I also hatched ducks with this batch and ended up getting ALL female except 1 male duckling. So apparently my luck has the opposite effect on ducks

I've hatched my own eggs from my backyard with a pretty general 50/50 male to female ratio, but for some reason all the shipped eggs I've hatched thus far has had a dramatic swing in males vs females.

 

[Auntiejessi3]

None of the things you've mentioned determine or influence gender.

 

[Canadian Wind]

If there were a way for us to be able to affect the gender of the chicks, there wouldn't be so many cockerels given away at the end of the summer.

Unlike snakes and other reptiles, temperature will not affect the gender. This is decided the same way human babies get theirs: by the father's sperm.

 

[JacinLarkwell]

If there were a way for us to be able to affect the gender of the chicks, there wouldn't be so many cockerels given away at the end of the summer.

Unlike snakes and other reptiles, temperature will not affect the gender. This is decided the same way human babies get theirs: by the father's sperm.

The females in poultry determine sex

 

[Canadian Wind]

The females in poultry determine sex

Okay, I learned something! Thanks Jacin!

 

[JacinLarkwell]

Okay, I learned something! Thanks Jacin!

No problem!

 

[pipdzipdnreadytogo]

Birds use the ZW chromosomal system versus mammals' XY system. In mammals, the male has the mismatched sex chromosomes, XY, while the female has the matched pair, XX. He passes down either an X or a Y chromosome that pairs up with the female's X to determine the sex of his offspring. In birds, however, it's the female with the mismatched pair, ZW, and the male with the matched pair, ZZ. Thus, the male always passes a Z, while the female passes either a Z or a W to determine the sex of her chicks. Some hens are said to throw more males or females, so there is some wiggle room there if you figure out which hen is throwing too many males and simply stop hatching from her, but that doesn't really help when you're buying eggs from someone else, unfortunately. Long story short, the sex of any chick was determined long before the egg it hatched from was even laid and incubated, and nothing we do will ever change that.

As far as temperature during incubation determining sex of the chicks, there have been studies on this. To my memory it wasn't that the temperature changed the sex of the embryo, it was that one sex was less likely to survive that temperature difference. And, as I recall, the temperature difference was so minute and the difference in embryonic survival so minuscule that it barely made an impact on the actual sex ratios in a hatch. In other words, you wouldn't set 10 eggs and get 10 pullets using this method, more than likely you'd set 10 eggs and get 5 pullets and 4 cockerels, or something more to that effect.

In the grand scheme, you're probably just experiencing a string of bad luck. Those percentages and odds such as the 50-50 chance of male or female hatching can skew when the sample size is small, for example in a couple dozen chicks, but the more 'samples' you add to the equation, the closer you'll get to those stated odds. In other words, keep trying and eventually your pullet count should catch up.

 

[Canadian Wind]

Birds use the ZW chromosomal system versus mammals' XY system. In mammals, the male has the mismatched sex chromosomes, XY, while the female has the matched pair, XX. He passes down either an X or a Y chromosome that pairs up with the female's X to determine the sex of his offspring. In birds, however, it's the female with the mismatched pair, ZW, and the male with the matched pair, ZZ. Thus, the male always passes a Z, while the female passes either a Z or a W to determine the sex of her chicks. Some hens are said to throw more males or females, so there is some wiggle room there if you figure out which hen is throwing too many males and simply stop hatching from her, but that doesn't really help when you're buying eggs from someone else, unfortunately. Long story short, the sex of any chick was determined long before the egg it hatched from was even laid and incubated, and nothing we do will ever change that.

As far as temperature during incubation determining sex of the chicks, there have been studies on this. To my memory it wasn't that the temperature changed the sex of the embryo, it was that one sex was less likely to survive that temperature difference. And, as I recall, the temperature difference was so minute and the difference in embryonic survival so minuscule that it barely made an impact on the actual sex ratios in a hatch. In other words, you wouldn't set 10 eggs and get 10 pullets using this method, more than likely you'd set 10 eggs and get 5 pullets and 4 cockerels, or something more to that effect.

In the grand scheme, you're probably just experiencing a string of bad luck. Those percentages and odds such as the 50-50 chance of male or female hatching can skew when the sample size is small, for example in a couple dozen chicks, but the more 'samples' you add to the equation, the closer you'll get to those stated odds. In other words, keep trying and eventually your pullet count should catch up.

Thank you very much! I usually just study colour genetics, so this had never come up for me.

Even at my advanced 56 years of age, I can still learn something new!

 

[Morelias]

Birds use the ZW chromosomal system versus mammals' XY system. In mammals, the male has the mismatched sex chromosomes, XY, while the female has the matched pair, XX. He passes down either an X or a Y chromosome that pairs up with the female's X to determine the sex of his offspring. In birds, however, it's the female with the mismatched pair, ZW, and the male with the matched pair, ZZ. Thus, the male always passes a Z, while the female passes either a Z or a W to determine the sex of her chicks. Some hens are said to throw more males or females, so there is some wiggle room there if you figure out which hen is throwing too many males and simply stop hatching from her, but that doesn't really help when you're buying eggs from someone else, unfortunately. Long story short, the sex of any chick was determined long before the egg it hatched from was even laid and incubated, and nothing we do will ever change that.

As far as temperature during incubation determining sex of the chicks, there have been studies on this. To my memory it wasn't that the temperature changed the sex of the embryo, it was that one sex was less likely to survive that temperature difference. And, as I recall, the temperature difference was so minute and the difference in embryonic survival so minuscule that it barely made an impact on the actual sex ratios in a hatch. In other words, you wouldn't set 10 eggs and get 10 pullets using this method, more than likely you'd set 10 eggs and get 5 pullets and 4 cockerels, or something more to that effect.

In the grand scheme, you're probably just experiencing a string of bad luck. Those percentages and odds such as the 50-50 chance of male or female hatching can skew when the sample size is small, for example in a couple dozen chicks, but the more 'samples' you add to the equation, the closer you'll get to those stated odds. In other words, keep trying and eventually your pullet count should catch up.

Yes this! Sorry I worded my previous statement not very clearly by using the word "formation". Yes, gender is determined by the hen while the egg is being formed. In the study I read, temperature didn't change gender, but showed that male embryos might develop differently than females, depending on temperature. Resulting in males having a lower rate of hatch.

Hopefully this is just a streak of bad luck and this next hatch will prove differently! Although I seem to have good luck with ducks, maybe I just need to hatch more duck eggs instead lol

Tysm for your response

 

[sqatkins]

If there were a way for us to be able to affect the gender of the chicks, there wouldn't be so many cockerels given away at the end of the summer.

Unlike snakes and other reptiles, temperature will not affect the gender. This is decided the same way human babies get theirs: by the father's sperm.

Actually, you have it backwards, Canadian Wind. The hen's ova determines sex in chickens, not the sperm from the male. Weird, huh? I have found this information on many different sources. Here is one example:

"Avian sex differentiation is not determined by XY chromosomes like it is in humans and most mammals (or even the XO system used by some insects). In those systems the sex is determined by the sperm, by what the male contributes to the offspring. By contrast, birds have a ZW system of sex determination (shared with butterflies, moths, fish and reptiles). In that system, sex is determined by the female within her ova, and the sex of offspring is not affected at all by the sperm which the male contributes. Some people think it is this difference which makes parthenogenesis possible for birds. Parthenogenesis occurs when unfertilized eggs see embryonic development." -- My Pet Chicken