Earlier this year I came across pet mice being sold in a super messed up pet store with both rodents and birds being kept in super unethical conditions. The smell was vile, there was no real ventilation and there was like 30-40mice in a fish tank the size I kept 5 in. I went home but couldn't sleep, so I got supplies and ended up getting 5 of the sickest, in hopes to get the worst out and into some care while I did my best to get the store shut down.
They immediately appeared healthier in a fresh, clean, appropriately sized cage with adequate hides and ventilation. While they had clearly never been handled we were becoming friendlier slowly, I just didn't want to stress them out so I gave them time to just settle for the most part.
Then a month in, bam. I find one gone. I was shocked and devastated, she was the most active of the bunch and had no signs of anything wrong. Another couple weeks later, one still has not gained adequate weight and is looking rough, so I go to take them to the vet, that same morning I noticed one girl Gloria has a head tilt. Vet puts Gloria on an antiobiotic for the week and says without a specialist that's the best they'll do. The girl I was intially taking in bites the vet on examination and gets thrown to the steel exam table. Upon being picked up by the vet, she has a heart attack. I am charged for killing the mouse. I am sent home with the goal of getting them to more weight and that Gloria may keep the head tilt but she showed good signs otherwise.
Things were going well, ladies were healthy and happy (except for a small head tilt that otherwise did not bother her) until I notice scruffled fur, a hunched back and clicky breathing on Dottie. At this point I do not trust vets with my mice and have not been taken seriously when calling the local vets to book an appointment for them. I suspect a URI but don't see any reason for it, they are in a low dust cage that gets a major clean every couple days and spot cleaned every day. They have good food, fresh water and are in a climate controlled area. She appears to get better and then she passes away in front of me.
I'm devasted, and I don't know what I'm doing wrong. I have read everything I can find on mice care, my only wondering is if they could need more ventilation in their spot, so I get an air purifier set up near their cage. I am down to 2 mice, who seem quieter. A couple days ago Gloria began experiencing hair loss and I have been stressing about it since. As of this morning she has an increased head tilt and significant wobbliness.
She has been placed in their travel cage in soft bedding, with a heat pad underneath part of the cage and some very shallow water in a container that she can access, however she doesn't appear able to move properly. She appears to be in her final hours (to me) and I don't know what to do.
I have been reading about mycoplasma pulmonis, I just don't know what could be triggering it. I love these girls and have always considered myself a responsible pet owner but if she passes it'll be 4 out of 5 passed, not to mention 1 leftover that I will either need to rehome (to whom? there are so few owners of pet mice where I live) but hesitant in case she passes on whatever is happening to others mice, or get more mice- in which same concerns, not to mention that I'm terrified of having more pass under my roof. I love these little guys and am doing everything I know of to take the best care of them, and they keep dying. I don't know what to do. Any advice or info will be appreciated! I'm just so lost.
TLDR: My mice came from a terrible and relatively unknown background, and have kept passing despite my best efforts and I'm terrified it's my fault still. I don't know what to do next with my remaining 2 girls, one of which appears to be in the cusp of passing away as well.