Okay I just discovered seramas and they are so stinkin cute
.
I will have to get some one day!!! I would keep it in my houseYou should get them
Coming from a totally unbiased source, of course
Honestly I have a full size cross beak that I wish could live in my house with meI will have to get some one day!!! I would keep it in my house
she has to have special mash three times a day and is very attached to me. She even pecks my arm so I’ll hand feed her she also tries to follow me into the house lol
But it is quite the interesting topic!
I will have to get some one day!!! I would keep it in my house
An interesting topic indeed!
First off, unlike in mammals and other XY chromosomal system species, the sex of a chick is actually determined long before conception. In XY-chromosome species, it's conception that determines the offspring's sex because it's the male that determines the sex of his offspring. The fertilization of an egg occurs when one lucky sperm out of a cloud of millions manages to fuse with the egg, and the subsequent sex of the offspring depends on whether that sperm is one carrying an X chromosome or a Y chromosome from the father.
In the ZW chromosomal system used by birds, however, it is the hen that determines the sex of her offspring by passing on either a Z chromosome or a W chromosome in her egg cell. The male's sperm will always carry a Z chromosome. That means each and every one of a hen's egg cells already has that deciding factor within it. Obviously, it never will become a male or female chick without the fertilization of a male... but what it becomes had already long been decided at that point.
As far as temperature-dependent sex determination, it does not occur at all in chickens based on studies I've read on it. I've seen a claim that dropping the temperature at an undisclosed point in incubation will change males to females that then can only produce male offspring, but those reports are from the late 90's and, well, nothing has come of it, so I suspect it's far more complicated than just that.
Some work has been done that concluded that embryos of one sex are sensitive to lower temperatures and embryos of the other are sensitive to higher temperatures. However, their findings were that it was a tiny, tiny adjustment in temperature to make a tiny, tiny percentage difference in the ratio of sexes in the offspring. In other words, were you to set 100 eggs, you would expect on average 50 males and 50 females. Unlike the popular belief that lowering the temperature slightly would adjust this, say, to 40 males and 60 females, what the work done on the subject found was that you would actually still get that average 50 females, you'd just instead get 48 or 49 males because of that tiny change in mortality of the male embryos. This doesn't make enough of a difference to bother with on the large scale, and on the small scale such as with backyarders like us... Well, you'd probably never even notice a difference has been made.
I have read that some other work on the subject found no conclusive evidence that there is a cause and effect between temperature of incubation and mortality of one sex or the other in the embryos. So does it really work? Eh, very little at best.
What I've experienced with the past several years of hatching is that it's just an odds game, and those odds do come back around if you hatch enough. Last year, I hatched 70 chicks. Early on, my hatches were cockerel heavy, but by the end of the year I had 35 cockerels and 35 pullets, exactly even. This year I had to cut back some, and I ended up only hatching 32 chicks from my breeding pens. Again, we were cockerel-heavy at first, but now that the youngest are old enough for me to feel pretty confident about what their sexes are, I have exactly 16 males and 16 females. So if you hatch enough, your numbers should even out eventually, just as a statistical likelihood based on the odds of getting a male or a female out of any one egg being 50-50.
Err, apologies for the novel!
Now, an extra interesting tidbit for you all: though birds generally do not exhibit temperature-dependent sex determination as a whole, just one avian species has actually been found to have that trait, the Australian brush-turkey. Interestingly enough, like many reptiles who also have temperature-dependent sex determination, the Australian brush-turkey buries its eggs in a mound to incubate via the warmth provided by composting of the mound and any sunlight that reaches it rather than incubating them using their own body heat like most birds do.
Fascinating, thank you for sharing! It makes perfect sense now that all those teeny tiny egg yolks each hen has are already determined to be one sex or the other!An interesting topic indeed!
First off, unlike in mammals and other XY chromosomal system species, the sex of a chick is actually determined long before conception. In XY-chromosome species, it's conception that determines the offspring's sex because it's the male that determines the sex of his offspring. The fertilization of an egg occurs when one lucky sperm out of a cloud of millions manages to fuse with the egg, and the subsequent sex of the offspring depends on whether that sperm is one carrying an X chromosome or a Y chromosome from the father.
In the ZW chromosomal system used by birds, however, it is the hen that determines the sex of her offspring by passing on either a Z chromosome or a W chromosome in her egg cell. The male's sperm will always carry a Z chromosome. That means each and every one of a hen's egg cells already has that deciding factor within it. Obviously, it never will become a male or female chick without the fertilization of a male... but what it becomes had already long been decided at that point.
As far as temperature-dependent sex determination, it does not occur at all in chickens based on studies I've read on it. I've seen a claim that dropping the temperature at an undisclosed point in incubation will change males to females that then can only produce male offspring, but those reports are from the late 90's and, well, nothing has come of it, so I suspect it's far more complicated than just that.
Some work has been done that concluded that embryos of one sex are sensitive to lower temperatures and embryos of the other are sensitive to higher temperatures. However, their findings were that it was a tiny, tiny adjustment in temperature to make a tiny, tiny percentage difference in the ratio of sexes in the offspring. In other words, were you to set 100 eggs, you would expect on average 50 males and 50 females. Unlike the popular belief that lowering the temperature slightly would adjust this, say, to 40 males and 60 females, what the work done on the subject found was that you would actually still get that average 50 females, you'd just instead get 48 or 49 males because of that tiny change in mortality of the male embryos. This doesn't make enough of a difference to bother with on the large scale, and on the small scale such as with backyarders like us... Well, you'd probably never even notice a difference has been made.
I have read that some other work on the subject found no conclusive evidence that there is a cause and effect between temperature of incubation and mortality of one sex or the other in the embryos. So does it really work? Eh, very little at best.
What I've experienced with the past several years of hatching is that it's just an odds game, and those odds do come back around if you hatch enough. Last year, I hatched 70 chicks. Early on, my hatches were cockerel heavy, but by the end of the year I had 35 cockerels and 35 pullets, exactly even. This year I had to cut back some, and I ended up only hatching 32 chicks from my breeding pens. Again, we were cockerel-heavy at first, but now that the youngest are old enough for me to feel pretty confident about what their sexes are, I have exactly 16 males and 16 females. So if you hatch enough, your numbers should even out eventually, just as a statistical likelihood based on the odds of getting a male or a female out of any one egg being 50-50.
Err, apologies for the novel!
Now, an extra interesting tidbit for you all: though birds generally do not exhibit temperature-dependent sex determination as a whole, just one avian species has actually been found to have that trait, the Australian brush-turkey. Interestingly enough, like many reptiles who also have temperature-dependent sex determination, the Australian brush-turkey buries its eggs in a mound to incubate via the warmth provided by composting of the mound and any sunlight that reaches it rather than incubating them using their own body heat like most birds do.
