I'm leaning toward it being a coon. I'd put some disinfectant on it. I think he's just weak, and that's why he can't stand. I had a roo lose half a wattle after a long fight between him and a tiny other roo (The one who lost the wattle was huge, and lost to a Silkie mix) He couldn't support himself for the next couple days, and the injury had nothing to do with anything close to his legs.
Good luck with your rooster!