Hello folks, I've got a chicken with a problem and would love some feedback. She's a 7 year old Americauna. There is a naked, slightly inflamed area around her vent. To one side of the vent there is a one inch diameter swelling. I don't see any sign of a scrape or other injury. She is otherwise quite healthy with good plumage, good energy and laying 4 to 5 eggs per week. My other 4 hens are fine. I've been told that she's quite old and this may be the beginning of her decline. Any ideas ? Thanks and happy chickens !