I was content to just let these two play out a while longer, to see if they revealed themselves over time. However, since introducing 5 new birds to the flock, and the removal of a little golden sebright rooster that was causing problems, these two have started a campaign of terror (ok, so that's a little dramatic, LOL), that has unfortunately included ripping a few back feathers out of the new birds. I have sequestered the dark one for a bit. See if that will calm it down, but both these birds are having issues, and with the aggression, I'm starting to think it's much more likely they are roo, though don't let that sway your opinion. I'll start with "light" and then "dark". Opinions on gender please. I believe they are a solid 5 months old...