Broken blood feathers. I deal with that alot since we have a feather picker who targets feet. You can always clean it up, & use Non pain relief triple antibiotic ointment on it. That's all I do.
Yes, broken blood feathers. Usually during molt this happens more, new feathers coming in have a blood supply until the feathers are fully formed. Once the feather is fully formed the blood supply withdraws and the feathers don't bleed anymore. When the protective sheath is broken on a forming feather, they bleed. Sometimes profusely. You can stop bleeding by applying pressure, or using blood stop powder, styptic, flour or corn starch. Sometimes they can be hard to get to stop bleeding, it's like a straw sticking in there, so in those cases you can pluck the feather and then apply pressure to the area on the skin to get it to stop. A pair of needle nose pliers works well, or a hemostat if you have one, grip the feather as close to the base as you can and give a firm tug to pull it. I had one rooster that this was a regular issue for, so when he was growing new feathers I would wrap his legs lightly with co wrap with the feathers in the direction they grew, just enough to help protect them until they were done. I've had other feather legged birds that never had an issue. I think roo's may be more prone to have issues due to their normal rooster behavior, but that's just a guess.
Im pretty sure its the broken feather thing. They are all molting right now. One of the black sex links is looking almost bald in some places. But the Roo has 2 broken feathers that the other birds are pecking at.