I just opened my breeder mouse cage, and one of my three females (my oldest one, though still not an old mouse) was huddled in the corner. I picked her up and she felt quite skinny. Then I looked at her head, and her whole face was swelled up, her eyes were kinda gooey and gross. Now, just a few days ago, she was fine. Though.. she had a litter, and I never saw a trace of any of the pinkies (I figured they ate them)

I just introduced two new females about a week ago. Maybe has something to do with it..

Either way, those new mice I got aren't as big as my old one, so I don't know if they can have a litter yet.. probably.. but I hope soon.

So.. I just gassed my breeder female mouse. Didn't want her to suffer any more.. she looked pretty bad.

Upon closer examination, I also discovered a sort of growth under her right fore leg (her armpit if you will) I know tumors are common among mice, but I'm not sure if that was it.

Puzzling.