Is it true the hens choose which sex they lay?

[Lady Ressler]

I was told by a friend that the hens are the ones that decide wether to lay a female or a male egg.

I thought this might be true because the eggs I bout from her came froma flock of two drakes and one of them was very mean to the girls. He would grab them by the back of their head like he was going to breed them but he would never step on. He would just bite and tug. Eventually all the hens left the mean drake for the romancing drake. All the eggs collected from these hen ended up being drakes except for 3 (out of the 14 that hatched). I just want some hens.

I would like to get some eggs form her again but I haven't had the best of luck with getting hens from her.

However, the mean drake was removed from the flock and "retired". Since then she has added about five more hens from other locations and intigrated different drakes.

So. What do you think? Does the hen choose what sex she lays?

 

[Fernleaf]

The hen's don't actually 'choose' which eggs to lay, the ovary releases the next ripening ovum which then travels down the oviduct to become a fully-shelled egg, but there is a roughly 50/50 chance that the egg could be a 'boy' or a 'girl' duck. There is a nugget of truth to the statement though.

In mammals like you and I all the eggs in a lady are by default 'female' because they all contain an X chromosome, while male sperm can be either X or Y. Thus it's the sperm (boy) that determines the ultimate sex of the offspring. XX = girl XY = boy. In birds that role is reversed, all the sperm are 'male' with a Z chromosomes, while the eggs in the hen are Z or W, so the ultimate gender of the chick is dependent on the egg.

So yes, the hens are the more important piece in the role of gender determination, but the hen herself has no conscious choice in the matter.

 

[CelticOaksFarm]

The ZW sex-determination system is a system that determines the sex of offspring in birds.



In the ZW system, the ovum (female) determines the sex of the offspring, in contrast to the XY sex-determination system, wherein the spermdetermines (male) the sex (Humans). In the system, females have two of the same kind of sex chromosome (XX), while males have two distinct sex chromosomes (XY). The XY sex chromosomes are different in shape and size from each other, unlike the autosomes, and are termedallosomes. Some species (including humans) have a gene SRY on the Y chromosome that determines maleness; others (such as the fruit fly) use the presence of two X chromosomes to determine femaleness.



The letters Z and W are used to distinguish this system from the XY system.



Males are the homogametic sex (ZZ), while females are heterogametic sex (ZW). The Z chromosome is larger and has more genes, like the X chromosome in the XY system.

 

[Kevin565]

The concept isn't actually unheard of. Several bird species can subconsciously choose the sex of their offspring. However, I do not believe chickens are one of the species that can do it.

 

[Lady Ressler]

I probably should have specified that I was asking about ducks but it doesn't seem to make a difference. All birds are this way? Is this correct?

This facinating and thank you for the great information. I love the science of breeding but the genetics seems to throw me for a loop sometimes.