Ok, so as promised, here's Poohbear's butt:



Normally, her vent is nigh on invisible, so the fact that it seems to be protruding a bit worries us; also the base of her tail seems a little bit swollen. I notice no redness (pic is pretty accurate, color-wise), but when she moves, it varies a bit how much her vent is visible.

Any theories as to what's going on and whether it's serious are welcome. Once again, no matter what the base of her tail might look like, she is 100% female; she has laid several eggs every summer for the past few years, even though she's never been with a male. I guess she just likes making them or something...