Sex of eggs

[phore]

Hi All
I was watching a show about reptiles and the sex of babies several varieties of reptiles and birds is determined by temp. I was wondering if anyone has tried this with chickens by using lower temps or higher temps at the critical stage to see if there is any difference in percentage of males to females.

I found the following on WIKIPEDIA

Temperature-dependent sex determination (TSD) is a system in which the temperature the eggs experience determine the sexes of the organisms that hatch[1]. It is most prevalent and common among amniote vertebrates that are classified under the reptile class[1], but is also used among some birds, such as the Australian Brush-turkey. It differs from the chromosomal sex-determination systems common among vertebrates. It is a type of environmental sex determination (ESD); in other ESD systems, some factors such as population determine the sex of organisms (see Polyphenism).

The eggs are affected by the temperature at which they are incubated during the middle one-third of embryonic development[2]. This critical period of incubation is known as the thermosensitive period (TSP)[3]. The specific time of sex-commitment is known due to several authors resolving histological chronology of sex differentiation in the gonads of turtles with TSD[2].​

 

[Ridgerunner]

It does not work with chickens. The sex is determined when the egg is laid.

If this did work, all the meat birds the hatcheries hatch would be male and all the laying chicks they hatch would be female. If it were this simple, it would be common knowledge and common practice.

In the terms of the Mythbusters, Busted.

 

[LaurenM23]

'Tis true...this one only seems to apply to reptiles...or at least not to chickens. Oh, how fabulous would that be though! Think of how many chicks could be saved certain death for being born the wrong sex for hatcheries!

There is some evidence that seems to suggest that the male embryos are sometimes better able to withstand higher temperatures, thus there appears to be a greater number of males in a hatch that ran too high. If this has any truth to it, this still isn't "caused" by the temperature...just an impact in the aftermath.

Regardless, keeping your temps on the lower end seems to be better than the higher end (with 99.5 to 100.5 being the best range). Keeping it on the low end can slow development (they might hatch a little later), but the higher temps seem to have the greatest negative impact.

 

[phore]

I know that it is very unlikely but has anyone ever tried to see if this would work?
Is there any other things like types of feed, minerals, vitamins or other home made substances that might influence sex of embryo? Just curious about possibilities.
Was thinking of trying some experiments this winter and next spring to see if I can come up with anything. Any suggestions would be appreciated.
Thanks

 

[panner123]

DO NOT MESS with MOTHER NATURE. Nothing will change the sex of the egg, not feed, heat or anything else. You have a 50/50 chance of an egg being the sex you want. Now if you have access to a lab and the knowledge, you might be able to fertilize the egg artifically with only female sperm. Bar anything short of that and you are back to a 50/50 chance.

 

[Ridgerunner]

I say go for it. It may be possible you can hit on smething that the commercial operations have not discovered dispite spending millions of dollars on researching this question. Then think how rich you will be!!! Of course do not look to me for money to fund your research. I think you will find out the same thing that everybody else that has tried this has discovered. Your odds are 50-50 if you have a large enough sample size for the odds to mean anything.

 

[phore]

Does anyone know where any of this research may be located? What parameters were followed and their results?
I don't have much of anything else to do until spring.

http://www.freepatentsonline.com/7167579.html

1. A method for determining the sex of a fertilized chicken egg, comprising: placing the fertilized chicken egg in a horizontal direction on an egg stand which is downwardly concave and has a substantially egg-shaped periphery, and which has a mirror-finished surface; taking an image of the whole fertilized chicken egg from directly above the fertilized chicken egg placed on the egg stand; inputting the taken image into an operation apparatus; generating two-dimensional contour image data of the fertilized chicken egg from the inputted image; extracting parameters which represent a shape of the fertilized chicken egg from the two-dimensional contour image data; and determining the sex of the fertilized chicken egg by using said extracted parameters.

 

[phore]

by J. MULDER & 0. WOLLAN

"Don't count your chickens before they're hatched," the old saving goes. True, you can't be sure any given egg will produce a live chick ... but you can make a pretty good guess at the hypothetical bird's sex before the smallest crack appears in its shell. The method is simple, works for all breeds and is so reliable that we raised 23 pullets from 23 carefully chosen eggs!

Here's the secret: If you want your brood to be mostly female, select and incubate only the most nearly oval eggs. Those with a noticeably pointed end produce cockerels. Many of the chicks-to-be you examine, of course (especially the first time you try this idea), will fall into an indeterminate range ... so pick only the most clearly oval shapes if you want future layers.

Commercial breeders cull and hatch their "female" eggs because pullets bring a higher price, Therefore, a fertile batch of "straight-run" eggs bought from a big dealer is likely to contain mostly indeterminate and pointed discards and give you considerably less than a 50-50 chance of hatching female chicks. To improve the odds, choose from your own hens' layings or ask a local chicken raiser to save his most obviously oval finds for you.

Sound hard to believe? The first time I heard of this trick, I thought someone was pulling my only-recently-rural leg. But try it ... it works!

Yolk testosterone varies with sex in eggs of the lizard, Anolis carolinensis.

Lovern MB, Wade J.

Department of Psychology, Michigan State University, East Lansing, Michigan 48824, USA. [email protected]
Abstract

In the green anole (Anolis carolinensis), a lizard with genotypic sex determination, yolk testosterone (T) concentration is greater in male-producing than female-producing eggs at oviposition, but the source and potential effects were not clear from previous studies. If yolk T levels are also sex-specific before eggs are laid, a period during which embryonic steroidogenesis is unlikely, it would strongly suggest that the difference in yolk T is maternally derived. We collected yolk samples from eggs shelling within the oviducts of anesthetized females, and then allowed these females to lay the eggs naturally. Eggs were incubated to hatching to determine sex morphologically, and yolk T concentrations were analyzed by radioimmunoassay. As is the case just after they are laid, yolk T is higher in male than female oviductal eggs. To our knowledge, this is the earliest sex difference reported for any yolk steroid. We suggest that maternally derived yolk T levels could influence sex by differentially affecting male- and female-inducing sperm, because fertilization occurs after yolk deposition and ovulation, while the egg is in the oviduct. Our results, together with those of an increasing number of studies, suggest that a relationship between hormones and vertebrate sex determination may be more widespread than generally appreciated.
Copyright 2003 Wiley-Liss, Inc.
​

 

[speedy2020]

Quote:

Yolk testosterone varies with sex in eggs of the lizard, Anolis carolinensis.

Lovern MB, Wade J.

Department of Psychology, Michigan State University, East Lansing, Michigan 48824, USA. [email protected]
Abstract

In the green anole (Anolis carolinensis), a lizard with genotypic sex determination, yolk testosterone (T) concentration is greater in male-producing than female-producing eggs at oviposition, but the source and potential effects were not clear from previous studies. If yolk T levels are also sex-specific before eggs are laid, a period during which embryonic steroidogenesis is unlikely, it would strongly suggest that the difference in yolk T is maternally derived. We collected yolk samples from eggs shelling within the oviducts of anesthetized females, and then allowed these females to lay the eggs naturally. Eggs were incubated to hatching to determine sex morphologically, and yolk T concentrations were analyzed by radioimmunoassay. As is the case just after they are laid, yolk T is higher in male than female oviductal eggs. To our knowledge, this is the earliest sex difference reported for any yolk steroid. We suggest that maternally derived yolk T levels could influence sex by differentially affecting male- and female-inducing sperm, because fertilization occurs after yolk deposition and ovulation, while the egg is in the oviduct. Our results, together with those of an increasing number of studies, suggest that a relationship between hormones and vertebrate sex determination may be more widespread than generally appreciated.
Copyright 2003 Wiley-Liss, Inc.

​

I will try 1 batch round egg and 1 batch point eggs next year to see how they're turn out. It is fun to do experiment.

 

[shellybean40]

I have a friend who uses the rounded vs pointed method. She carefully chooses her eggs for hatching and she has a higher hen to roo ratio. She got the advice from a 90 year old woman who has raised chickens her whole life. who knew?