Thank you, Pyxis for taking the time to share that information.I am very sorry if you perceived me as attacking you. That is not my intent and I don't mean it to come off that way. I only mean to educate; that's why I have an Educator badge
TSC very often mislabels their chickens. I know, I used to work there and had to fix it ALL the time. The staff aren't given any kind of training. In the past I've purchased 'blue laced red wyandottes' which were red sex links, 'barred rocks' that were dominiques and, on one memorable occasion, 'white leghorns' which were broad breasted turkeys. The pictured rooster is not a black sex link male, and since he was bought and not bred there's no way to confirm the parentage, but I can be sure his mother wasn't barred.
Let me explain why it works the way it does and why it's impossible for a rooster from a black sex linked cross to not be barred. Chickens have different chromosomes than we mammals do. While in school you probably learned about X and Y chromosomes, and how female mammals are XX and male mammals are XY.
Birds are different. Birds have Z and W chromosomes. Female birds are ZW, and males are ZZ. Because of this, the way gender is determined in birds is also different than it is in mammals. While in mammals, it is the male that would provide the X or Y chromosome that would determine the gender of the offspring, in birds it's actually the female. Each egg is either a Z, which will be male, or a W, which will be female. The male bird provides the additional Z chromosome, which has no affect on gender.
Now, barring is what we call a sex-linked trait. In birds, this means it's a trait that's linked to the Z chromosome. You'll notice that since female chickens can only have one copy of the Z chromosome, they can only ever inherit one copy of these traits, while males can inherit two. That's why males can be what we call 'double barred', where they have thicker barring bands than females, and females can only ever be single barred.
Those are the basics. Now we can look at the mechanism by which barring is inherited, which explains why it's possible to make sex linked crosses using it and why it's impossible for a black sex link male to not be barred.
When breeding, a hen either passes on one Z chromosome, which would make the chick male, or one W, making it female. Remember that the barring gene is linked to the Z chromosome - there is no copy of it on the W chromosome. So now we take a barred female, who has the barring gene in her Z chromosome, and a non-barred male, who has no barring genes on his Z chromosomes to pass on at all.
If a hen is barred, then she must carry the barring gene on her Z chromosome. So it follows that all the Z chromosomes the hen is passing on contain the barring gene, so all of her sons are inheriting this from her. This means that all of them are barred. The father, the rooster, has no barring gene, so none of the daughters inherit it from him, nor do they inherit it from their mother, because that's impossible.
The result is all barred males and all non-barred females. There's no way for a male to not inherit barring when breeding this way. Now, could a non-barred male result as a freak mutation? Sure, I won't say it couldn't happen, all colors started out as a sudden mutation. But the odds of that happening are astronomically low, so low as to be pretty much negligible.
Here's a quick chart I whipped up to visually show what I'm saying here:
View attachment 1996327
Here is also some further reading you can do, if you want to learn more about this:
https://www.hobbypoultry.com/the-barred-gene-use-in-chickens/
https://www.backyardchickens.com/threads/sex-linked-information.261208/
And here is a chicken genetics calculator you can play with, too. If you put in a barred female and a solid male, you'll see that the only possible results are barred males and solid females:
https://kippenjungle.nl/kruising.html
If after reading this, you still think that a black sex link rooster could be solid and not barred, then we will agree to disagree and I will not post about it again![]()