It’s neitherHow do you know the Barred Rock isn’t a Dominique? I have Dominiques, and I can’t for love or money tell the difference between the two. I know, in theory, Doms have rose combs, but I have some single-combed ladies. I for sure can’t see the difference in the stripes. Apparently Rocks have cleaner lines, whereas Doms are more mottled.
In any event, your Barred looks more or less like my Doms did at that age — all are hens (though Lady Constance does have that tail…).