She needs a cuckoo roo in order for all the first offspring to be cuckoo. But the males hatched would be Heterozygous for cuckoo. Males would be (B/b) and females (B/-)I just read somewhere that in order for the cuckoo gene to be expressed, you had to have a cuckoo roo. Is that incorrect?
There is a sex-linked dilution barring gene but I’ve never seen it because the barring in my cuckoos and barred rocks behave the same genetically.