That is true, however the term "double barred" refers to roosters who have 2 barring genes. As the barring gene is only carried on the male Chromosome, hens cannot have 2 copies...so I cannot understand when people use the term "double barred" when referring to hens?
I am not trying to correct...
This is a good photo that has both"single" and "double" barred roos. Actually one of them may be simply buff...hard to tell in the pic
If you'll notice two of them are quite a bit lighter shade with the "lemon" colored hackles and white under carriage, as well the one in front has the darkness...
He does not appear to be "double barred" , meaning he only has a single copy of the barring gene. If so you will get a mixture of buffs and Lemon Cuckoo when bred with a buff hen.