Plucked back indication of sex?

[Kitei]

Split my chicks into groups today (they're a few days off 6 weeks) after noticing that one of them had a bare back with a spot of blood.
It's a dark faced cinnamon, so I can't really tell the sex, but would a plucked back be an indication of sex at all? I noticed one of the other chicks, a confirmed red breasted blue cock, also shows signs of plucking on his back, and was wondering if it was due to the cocks becoming territorial and attacking the other cocks, as none of the hens have showed any signs of it?

 

[GrandmaBird]

my hen does this to the male when she wants nothing to do with mating....so do not blame the males. I believe that is what is happening to your chicks. It sounds like it might be time to separate the males and females. and soon to pair up our chicks. good luck

 

[Kitei]

Oh, I wasn't blaming them. I just was wondering if it'd help me sex some of the more difficult birds - in particular, the tuxedos and silver, as I noticed that none of the confirmed hens had plucked backs, but there were signs of it on the red breasted males. If it is a case of the hens doing it to the cocks, then that'd still give me an idea of what I have.

I have started splitting the confirmed birds, as I said, but I was struggling to figure out what the tuxedos were. I think I have a silver tuxedo cock, another tuxedo cock and one hen. Not sure about the silver but there's no plucking there and it has an ivory bib rather than white, with no black or grey, so hopefully that's a hen. In which case, I have a dark faced silver male on his own at the moment, so if it's a hen I shall put it in with him in a few weeks.