Sneebsey
Songster
@EggSighted4Life for 100% blue offspring with sex linkage, one can use a splash cockerel over black barred hens. The offspring will all get one copy of the blue gene from dad and the boys will get one copy of the barring gene from mum. I would guess that if RIR have been used, it would be to develop one of the parent lines of the cross to be good layers. A barred cockerel over red hens would create all single barred offspring, so the hens of those would all be barred and could make up the maternal line for the hybrid.