Does incubation temperature affect sex of developing chick embryo

Discussion in 'Incubating & Hatching Eggs' started by Chicken Keith, Mar 12, 2011.

  1. Murgatroyd

    Murgatroyd In the Brooder

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    Sep 13, 2013
    That article mentioned experiments by others suggesting that pulsing eggs with high-low temperatures caused sex reversal in embryos, but it goes on to say those experiments could not be reliably duplicated.

    The featured results of the main article showed that pre-hatch mortality of brush-turkeys was sometimes greater in males due to environmental temperature and sometimes greater in females. I had to read the article closely or I might have missed the main focus.
     
  2. gocats719

    gocats719 Hatching

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    Apr 11, 2017
    Chicken sex chromosomes are Z and W. Somewhat like the X and Y chromosome in humans. The difference is that in humans the female is XX and the XY chromosomes of the male determine the sex of the child. If the haploid sperm gamete the does the fertilization contains the X chromosome the the child will be a female. If it contains the Y chromosome, then the child will be male. In chickens the male sex chromosome is ZZ and the female is ZW. Therefore it is the female chromosomes that determines the sex of the chick. The process of meiosis produces four Haploid sperm cells each containing one Z chromosome whereas I the female meiosis produces four haploid cells. Two with the Z chromosome and two with the W chromosome. Of these four only one survives with a 50/50 chance of it being a Z or W chromosome. These means that half the eggs produced by the hen will have the female producing W chromosome and half will contain the male producing Z chromosome. Once fertilization occurs the sex of the chick is imediately determined. Any variation of temperature, during incubation, would only lead to more Roos or hens, if a higher or lower temperature lead to the demise of one sex or the other. In other words, if female chick are more susceptible to death at higher temperatures then you will have a higher percentage of males because the embryos that don't develop or die before hatching would mostly be females. If them male chicks are more susceptible to death at lower temps then you will have more hens at lower incubation temps because those that don't hatch would more likely be males. (I don't know this to be the case but that might explain the discrepancy in the ratios of chicks. If one were to have an unheard of 100% hatch rate the ratio will be approximately 50/50. Hope that helps
     
  3. AbbysSilkies

    AbbysSilkies Chirping

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    Jul 31, 2017
    Wait really?!? Someone gave me ee eggs and they were all blue darn it
     
  4. ronkonkoma

    ronkonkoma Songster

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    May 4, 2014
    Long Island NY
    I know this is an old post but this is the way I understand it as well. I did incubate at 99.5 but messed up humidity and it was high the entire 21 days and I ended up with 6 boys and 1 girl or 7 boys. (Chicks from another hatch mixed in and 2 whites looked exactly the same.) I am getting 4 gorgeous hens from 2 very reputable breeders and I'd like to hatch a couple right when I get them, because they were fertilized by their roos, but I dont want any boys haha. I think I'm going to try to incubate at a lower temp and see what happens. [QUOTE="gocats719, post: 18334605] Any variation of temperature, during incubation, would only lead to more Roos or hens, if a higher or lower temperature lead to the demise of one sex or the other. In other words, if female chick are more susceptible to death at higher temperatures then you will have a higher percentage of males because the embryos that don't develop or die before hatching would mostly be females. If them male chicks are more susceptible to death at lower temps then you will have more hens at lower incubation temps because those that don't hatch would more likely be males. (I don't know this to be the case but that might explain the discrepancy in the ratios of chicks. If one were to have an unheard of 100% hatch rate the ratio will be approximately 50/50. Hope that helps[/QUOTE]
     
  5. Chickenhatching478

    Chickenhatching478 Hatching

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    Jan 17, 2019
    I did a little experiment using the Janoel 10 incubator where instead of the temp being 37.5 I made it 37.4 because I researched and found that male chicken embryos are much more sensitive to the cold. Even one tenth of a degree too cold the male embryos will die a few days into developing. Females would die to if it was too cold. So I had to find the right temperature for the Roos to stop developing and the hens to hatch.I decided to try this because I already have many Roos and I didn't know if I would be able to find a good enough home for the Roos I might've hatched in that clutch. Sure enough, I candled all the eggs on day 4 they were all developing, then when I candled them on day eight two of the eggs had stopped developing! I'm thinking they were gonna be little Roosters. When the eight other eggs hatched they were all female!
     
  6. Chickenhatching478

    Chickenhatching478 Hatching

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    Jan 17, 2019
    NOTE-I am not saying the temp changes the sex because that is impossible for chickens, I am saying that colder temperature causes the more sensitive embryos (male) to die a few days into developing.
    This might have been a fluke but I am thinking that this is a very valid theory. I would love to see you guys try this experiment and tell me how it works out for you. If this is a valid theory it could be VERY
    helpful for all chicken lovers. So please share your results!
     

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