Just to clarify further, I want to explain why it is absolutely impossible for a pullet that has a non-barred father to be barred. It's all down to a chicken's chromosomes.
Human chromosomes are different from chickens. While in humans we are XX and XY, with females being the homozygous XX, in birds it's different. Birds are ZZ and ZW, and the males are the ones that are homozygous. Females are the heterozygous ZW.
And also unlike in humans, where the chromosome the male donates determines the gender of the offspring, in chickens it is the chromosome that the female donates that determines the gender of the chicks. Each egg is either a Z or a W. Then the male donates one Z chromosome to fertilize the egg and the chick develops.
Now, barring is a sex linked gene, meaning it is linked to the Z chromosome. So, barring is only located on the Z chromosome, not the W. This is also why only male chickens can be double barred, because they can get two copies of the gene because they have two Z chromosomes. Females, only having one Z chromosome, can only get one copy of the gene and thus can only be single barred.
So, a barred hen has the barring gene on her Z chromosome. Barring is never on the W. What this means is that, since the hen only contributes a W chromosome to her daughters, she cannot pass barring to them. And, she contributes her Z chromosome with the barring gene to all her male offspring, meaning they are all barred.
A rooster that is not barred has no barring gene on his Z chromosomes, so he cannot pass barring to any offspring.
What this results in is all males from a barred hen under a non-barred rooster having one copy of the barred gene and being single barred, and all females getting no barred gene and being non-barred.
So, I hope this helps explain why it is entirely impossible for a pullet to hatch barred from a barred hen bred to a solid rooster.
