Do Bielefedlers have to be separated from other breeds to preserve the Autosexing gene?

[peaceful_pastures2020]

I have 6 week old Bielefedler pullets & 3 week old Bielefedler cockerels. I'm trying to decide which coops to put them in & I thought I read somewhere that the breed needed to be separated from other breeds to preserve the autosexing gene. Is this correct? I will have them separated when they're older & I would like to breed them, but do they need to be separated in the mean time? Thank you!!

 

[nuthatched]

If they breed with the breeds they are housed with, the chicks won't be sex able (depending on the other breeds) I think.
But the beliefelders won't change.