My rooster is around six years, not old by my flock standards where chickens reach twelve, thirteen, fourteen years.
His lesion is twice as large as what has been pictured in my thread. It's another reason I believe it's a cancer lesion.
When I discovered it a year ago, it was bloody and I assumed it was an injury. Now I believe the cancer was growing on the leg and then he injured it. Whenever I treated it as an injury, debriding, etc, there has never been any sign of pus, just a thin black scab in the center, surrounded by raised tissue that has now expanded beyond what it was a year ago when I first discovered it.
My flock has the leucosis virus. This is what I suspect is the source of this tumor.