Who dies, hens or roos.

In reading another thread, Coopslave and Country Thyme? (forget already, the brain is not working right these days, sorry) said that pullets die in the eggs more often than roosters.

I need to know. Is this conclusion based on medical examination of the dead chicks in the shells? Or is this conclusion based on the fact that more roosters hatch than hens in a batch?

In all other living things, well MOST other living things, the FEMALE embryo out toughs the male 10 to 1. It goes against the popular wisdom to say that in birds it's the other way around. But it might be! I have just never heard this before. I am wanting to know what hard scientific evidence there is to support this claim.

I am interested in incubating and if there was a way, in an incubator, to thin out the MALES, I'd sure like to figure it out. SO would the chicken industry as a whole! I would like to hear further discussion on this topic, as I've never before heard that temp spikes kill more females than males. This is very interesting.

Country Thyme was saying that with ducklings it is usually the drakes that make it out fine, but if there is a temperature variation the hens may die in the shell.

Uno, I met a fellow at a market sale that swore he had discovered the way to make more girl birds using natural incubation, it was to do with the type of feathers on the broodies. The ones that worked had hard feathers, not as much heat transfer in first few days he thought, but I wondered if it was the intermittent sitting at first that produces more, so according to him, sex determination does not occur at fertilization but instead in first three days of incubation, could explain why as a whole, hens will raise more girls than boys for me, unlike in the incubator which I think is pretty much 50/50.
Here is his quote:


The bantams that make virtually all females are Old English x Dutch. Cool incubation makes females, hot makes males. As I think I said the other day you can get Old English and Dutch here in Canada but they don't go broody, least mine never did.
Try a few different types of broody bantams and see what happens. It's only the first three or four days incubation that matters when determining the sex, after the first four days you can pull the eggs and give them to another broody or put them in an incubator. That way you can make loads of females from just one broody, when you find a bantam that does the business that is. I used to keep them broody for up to two months sometimes before letting them have a clutch to hatch and rear.

I was considering incubating at 37.5 first 3 days then turning up to 37.6 which is what I set my Ovaeasy 190 at usually.
Worth a try I guess!

When an egg is created it gets half it's genetics from the daddy, including an X OR a Y sex cell. Same from the mommy, only she can produce and give only an X.

So each egg, when it pops fully formed from the mom has either XY and will be a male or XX and will be a female. There is no opportunity for change after that.

In theory you should get 50% girls and 50% boys. However the odds are never perfectly even and other factors may skew your results.

Since we can't control nature's method for choosing gender, the trick is to find a way to cause more male embryos to die early in the egg and not develop which is I think what Uno meant by "thinning out the males" Whether that is something that can be controlled through carefully planned temperature fluctuations, I don't know??

I'm really interested in what Miry was told about cool incubation for the first few days to skew the odds more in favor of females.
This would agree with that fact that in most species, the female embryos are more resilient and able to survive less than perfect conditions. That's well documented.
However....

Last season I definitely hatched more females than males. This year I seem to have produced a higher ratio of males. I've been using the same incubator, have not changed any settings, so why do the ratios change? Changes in breeding stock, ie healthier or less healthy genetics? I will have to think about this more and examine carefully if I have changed anything from last year such as egg storage, collection etc...
Too many questions, no answers here!

Last year I had more females too... and I hatch at 99.2 degrees since that seems to work better for the Houdans. I will see if this continues this year.

However, I usually have 100% hatches from the eggs that are fertile to begin with so the cooler temp theory does not seem to apply to me.

For me, there are too many unknowns to draw a conclusion.

I think before we can determine that male embryos are stronger, or female embryos survive initial low heat, we have to determine the sex of the egg the second it falls out of the hen!

Since no one has ever been able to determine if an egg is male or female at the moment it's laid, there can be no conclusive evidence about how heat or lack of heat determines the sex of the chicks. There is only anecdotal evidence gathered from our observations. So while we may OBSERVE more pullet chicks from hard feathered broodies, we have, in fact, no way to determine if that is true or just plain luck.

It seems to me that in every hatch I've had, I get more than 50% roosters. But I have also heard that when you hatch small numbers you notice this more, but if I were to hatch hundred of eggs, the overall ratio of hens to roosters would be around 50/50.

All I know is it's a gamble.

I do not believe there is a way to change an egg's sex, or make a male egg turn into a female egg. If anything, there might be a chance that different hatching methods (heat, humidity, frequency of turning) might have an effect. But until we know how many eggs are destined to be boys and girls, we can never know if it was boy eggs or girl eggs that died in the process. We can determine NOTHING from our end results until we can know what we're starting out with. And so far, we don't know that.

.

So Tara, that means the female determines the gender of the chick? What an interesting titbit! Thank-you!

So you are also saying that when an egg drops from the hen, the gender is already determined?

I certainly have to make a switch from my mammal-centred mind!

Hey, I knew this one!

In reptiles - like alligators - sex can be determined by the temperature during incubation. Above a certain temp, you get all one gender, below, you get all of the other.

Sadly, I learned this by watching children's cartoons. Wild Kratts!

I did know it's not the same with mammals, though.

authenticfarm wrote:Hey, I knew this one!

In reptiles - like alligators - sex can be determined by the temperature during incubation. Above a certain temp, you get all one gender, below, you get all of the other.

Sadly, I learned this by watching children's cartoons. Wild Kratts!

I did know it's not the same with mammals, though.

Wouldn't it be nice to be able to choose the sex of your next child by either cold baths or soaks in the hot tub?

Schipperkesue wrote:Wouldn't it be nice to be able to choose the sex of your next child by either cold baths or soaks in the hot tub?

Hahahaha!

I really wanted a girl for my first one. And I got one. And then when we found out about our little oops baby, I thought having another girl would be really efficient, since I already had all the stuff for a girl. So I had another girl. And now I am done. lol

Also, whenever I spend time with little boys, or families with all boys, I am REALLY REALLY happy that I have two girls.

/hijack

Yes, the terminology is ZW rather than XY and it's determined by the ovum. I've always thought that, if there is higher survival amongst mammal females, it is due to the extra genetic material on that X chromosome. I suppose, if that were the case, then we might expect to see more rigor among male birds (since they're the ones with more genetic material, having the ZZ instead of ZW). Interesting to think on.

HigginsRAT wrote:Heel low:


This has been disproven and in my opinion, therefore a waste of efforts.

I personally welcome both genders in our poultry. In conservation breeding, we want an even number of males and females so that we may keep the genetic options open. No gender is more important than the other. Gender equality ROCKS!

Doggone & Chicken UP!

Tara Lee Higgins
Higgins Rat Ranch Conservation Farm, Alberta

I agree that both genders are equally important and I wouldn't consciously set out to try to produce more pullets. But I do find it very interesting when some years I have a noticably higher ratios of one sex and it would be good to know if I have inadvertantly made it happen that way during incubation.
Now, I'm not talking huge variations, but maybe 55% to 45% rather than 50:50. But when looking at a group of 100 or more youngsters in growing pens, it does become noticeable.
I rarely have a batch of eggs make it all the way from collection through to hatching and end up 100% viable. Out of a batch of 40 - 50 eggs I normally remove a few when I candle at 10 days that either didn't begin or have quit developing, and there may be another 2 or 3 that develop fully but do not hatch. So there is room in there for some sort of gender-selection happening in mysterious ways in my incubator.

It is a good discussion!

In statistics it is important a large enough sample is used and that the sample is diverse, so a sample of 25 Cochin chicks that I hatch during the same time period at my farm is not a large enough sample to draw a valid conclusion. The sample is far too small and too restricted to be accurate. I just completed a stats course on testing (children of course) and the sample they took to norm a test they were creating was thousands of children from all across Canada.

I would have to think that if there was a reliable way to determine if you hatch more hens than roos, the laying bird industry would be doing it whole hog. As it is now, roosters of the laying bird variety are pretty much waste birds. The laying industry comes under fire for creating birds that are destined to die for no reason other than their gender. If anyone has a vested interest in hatching fewer males, it's the layer industry. But they don't. They hatch what they hatch. Coming even more under the glaring eye of public disapproval. This tells me that determining sex by incubation methods is a no go.

There may indeed be a higher death rate in male or female eggs, but what's causing it seems to be up for debate.

Sue, hope you enjoyed your statistics course. WHen I took it in college it gave me brain bleed. But the only thing I recall from the course was what the prof told us on day one: NEVER BELIEVE A STATISTIC!

Ha ha! Maybe we had the same instructor. I did enjoy it Uno, but it was pretty specialized and the instructor was great. I can imagine it would be pretty dry stuff if there was no practical application.

57% of statistics are just made up.

I've been away for a couple of weeks, but I see that the truth has come out.

Sex is definitely determined at conception, just as with mammals.

Female birds have slightly less chromosomal material than males - just that one Z (plus a tiny little W), vs 2 Zs for the males. And it's been observed in mammals that the males (so called heterogametic sex), being unbuffered by that extra chromosome, do tend to have a higher mortality rate - e.g. 104 male people born for every 100 females; males die off faster so they're approximately equal through late teens and 20s, then females predominate right through to the end, where you see a pretty skewed ratio in old-folks' homes - lots of women, few men.

Any recessive genetic disease that is carried on the Z chromosome (i.e. sex-linked) will have a higher chance of being expressed in the female than the male - if the prevalence of the gene is, say, 10%, then 10% of females will have the disease, but only 1% (= 10% squared) of the males. This is like red-green colour blindness, or hemophilia.

As uno says, if there were a way to influence or determine sex easily before hatching, the egg inustry would have been onto it by now.

Thank you for that ipf. The truth IS out and the truth is that 57% of statistics are made up.

I think Fowler is made up.

I think he is 100% an invention of his own imagination. Or a figment, as we euphemistically call it. A statistical anomaly. A poorly controlled study group. A glitch.

.

Very interesting. I had a friend who paid big bucks for a dozen Welsummer eggs and got 8 roosters out of them in the end. NO hens. She was disappointed, but I traded one of the roosters for a RIR pullet, so I was happy.