Predominant Sex??

[rizq]

The sex of an individual is generally determined genetically by genes on one of the two sex chromosomes. In mammals, for instance, the presence of the male-specific Y chromosome confers maleness, whereas in Drosophila melanogaster and Caenorhabditis elegans it is the number of X chromosomes that matters. For birds (males ZZ, females ZW), however, the situation remains unclear ...cut... Clearly defining the roles of the DMRT1 and PKC1W genes in gonadal development, and ultimately determining whether avian sex is dependent on Z or W, will require transgenic experiments.

copied from http://www.nature.com/embor/journal/v2/n3/full/embor459.html

Apparently, they are unsure exactly who determines the sex of a bird or why. At least according to two websites that I skimmed. I don't have time for more ... would still like to see other sources from any side of the argument.​

 

[Laskaland]

Quote:
Thanks Becki!
I would really appreciate learning anything you find

Christina

 

[speckledhen]

Quote:
It is reversed in birds, that's true. A hen's offspring have their sex determined before she even lays the egg, I've read. Some will throw more girls than boys or vice versa.

In incubation, if there is a problem, usually more males survive that.

 

[hinkjc]

I did several hatches over summer for a chicken project and I found that out of 80 birds grown to sexing age, it was exactly 50/50.

I think you have to hatch more than a few eggs to get to that result, but that is the typical result in the end.

As for quail, we grew out 18 white bobwhites last season and ended up with 14 males. Eeeek!

Jody

 

[Laskaland]

Quote:
It is reversed in birds, that's true. A hen's offspring have their sex determined before she even lays the egg, I've read. Some will throw more girls than boys or vice versa.

In incubation, if there is a problem, usually more males survive that.

Cynthia, when you say a problem with incubation, is that too high of temp or is it a humidity problem? I'm just curious b/c I seem to hatch many more boys than girls and I want to figure out why.
Thanks so much!
CHristina

 

[speckledhen]

Anything in the bator that causes embryos to die is what I mean, such as a temp spike. The tougher ones are the males, so they tend to survive mishaps. It doesn't create the sex, just manages to kill off the female embryos.

 

[Laskaland]

Quote:
Can I oick your brain a bit more, Cynthia?
Is there a specific time frame within the 21 days where the temperature is the most important? And is it true that a lower temp is perferable to a higher temp?
Thanks for the info
Hugs
Christina
(who is getting better results the longer I try at incubating)

 

[speckledhen]

Lower temps are better than high temps, if they have to veer from the normal ranges, as they usually just prolong the incubation period. I dont know if there is a certain time that the high temps would do more damage, though.