Hi Chickengr nice if you can get some fertile eggs from the new breeder new blood line you can mix t with your in the future.
better if you put your pullet with the older rooster not her brother.
mating a sister chook to her brother cockerel for ones is not that bad like the people think is actually good to see what sort of recessive genes they carry .
I use this technique my self to multiply a rare strain before I ll cross them to some thing else .
my chooks don t let me have my first coffee in peace .they are on my case at 5 am .especially the Roosters.actually just the roosters the hens are angles tell they lay they eggs .than is different story, they turn to show the rooster how much noose they can make.
guess they is the way of life with a chooks.
chooks man