Questions about the 50/50 ratio in hatching

your theory makes sense to me

 

Back in statistics class in university, the professor used to say, "flip a coin 10 times". then, "flip a coin 100 times". In other words, 50/50 is what happens over a long period of time, on average. When our "sample" is just this particular rooster and these few hens, perhaps, it can be skewed. Hatch out 1000 chicks from 10 roosters and 100 hens? Probably be much closer to 50/50.

There is also some evidence, not much, but some, that incubation temperatures can skew the hatch rates too. Wish I could remember if hotter versus cooler produced what? I just cannot remember. LOL

 

As far as I understand it, each egg individually has a 50/50 chance of being a certain gender.

This does not mean with a small sample size that you will get a 50/50 ratio. It is the same as flipping a coin. If you flip a coin only 4 times you might get 2 heads and 2 tails but you might get 4 heads. Each individual flip has a 50/50 shot just like each and every egg has its own 50/50 shot at beng a certain gender. What happened to the egg that was laid before it or after it does not effect that particular egg's 50/50 chance. (If 5 chicks have all hatched roosters and one egg is cracking, that unknown egg still has a 50/50 shot of being a rooster)

Statistically and mathematically speaking if you flip enough coins or hatch enough eggs each with their own 50/50 individual shot then the overall ratio will be close to 50/50. The more eggs the closer you will get to that ratio. (lots like 1000s)

So, if you were to look back at your hatch rate over a lifetime of breeding your overal ratio will likely be very close to 50/50 however this may not be evident with each individual hatch containing a small number of eggs.

Here is a good explanation on 50/50 statistics:

http://www.basic-mathematics.com/coin-toss-probability.html

 

In my expirience, the Hen makes the difference, some hens lay more female eggs and some lay more males. You just have to find the hen that lays more females. I like what your trying to do with your varibles and taking advantage of them but unless you know who is laying the mostly females and who is laying mostly males it will be hard to find the proper angle to work from.

50/50 shouldn't be that hard, with the most variables applied you should get close. So get as many as you can from as many different times and as many different hens that you can and that should be as close to random as possible which will yield closely to what is natural. 50/50

From there take notes on which hen layed what if you can and next time around pick eggs only from the hen who layed mostely females. That can get your numbers into the 60/40 range but beyond that its a crap shoot.

 

deleted because the information I posted was incorrect. Please see below for a great explanation of ZZ:ZW chicken genetics.

 

Is that right? Are birds the same as mammals? I remember reading something about ZZ. Have to check that out.

 

Instead of XY, birds have a ZW chromosome system where the ovum determines the sex of the offspring - males are ZZ, while females are ZW (the W chromosome plays almost no part in physiology).

My statistics prof used to say that if you torture numbers long enough they will tell you anything you want to hear.

 

I don't agree with the above in mamals yes, in chickens no.
In chickens gender is determined not by X and Y chromosones. But rather by ZZ:ZW chromosone system. That of which is highly affected by the estrogen. The chicken embryo resembles lower vertebrates in that estrogens play a central role in gonadal sex differentiation. Not to say she can choose but she does infact influence her offspring. In case your wondering ZZ is the boy and ZW the girl.