my mouse may be sick

Question
Ok, so comparing the behavior of my mice to one another and noting that one has already died,
I think its safe to say my other mouse is sick. The first one died after difficult-to -determine untill you're too far gone symptoms occured and now my other mouse is showing some of the same symptoms at a slower progressing rate. These symptoms include: fast, shallow breathing(more than normal) restless behavior, sleepiness(she sleeps a lot when she can) stock-piling food(if that helps; she's been doing that intensivley, more than my two healthy mice) thinness(you can almost see her tail verabre and can definativley feel her bones, though she carries a bit of weight around her belly below) picky eating behavior(which I've tried to correct) being obviously underweight, and having pale skin beneath her fur and on her paws and tail.(she's brown/gold in color) she is also smaller than the other two. I did try to breed all three females I had, but I very much doubt she's pregnant(the male has been out for two weeks and neither of my mice still living are showing any signs. I'm trying. To get her to gain weight by feeding her birdseed, which she eats a lot of, oatmeal(raw) sunflower seed kernels, corn and peanut butter. She is eating a little by little. Thanks for listening to my panicy rant, and sorry for the length.

Answer
Hi Samantha,

The part of your description of her symptoms that concerns me the most is her weight.  The other issues, like rapid shallow breathing, can be signs of stress, but not necessarily illness.  If she had been cagemates with the mouse you recently lost, it is entirely possible the two issues are linked - mice do grieve their friends and family and may manifest this in all the ways you have described.

Sometimes a thin, ragged, lethargic appearance can also result from dehydration.  Try checking her water bottle each day by tapping it with a finger to be sure it is functioning - it can be easy for a small piece of bedding to clog the sipper ball and prevent it from functioning or cause it to leak.  You can also beef up her diet with some high protein foods.  Some good options to try are scrambled eggs made with water or kitten milk replacement instead of milk, mealworms (these tend to really excite mice!), or even dry cat kibble mixed in with her normal food mix.  Don't forget to include a commercial mouse diet (either a seed/pellet mix or food blocks), as these contain trace vitamins that are required to keep her going strong and raise her immune system.  Cheerios are also a great treat that can be used to entice her to eat, but they, like anything besides her normal mouse food, should be fed as treats.  I would avoid the corn and the peanut butter personally - they may be delicious, but peanut butter can be a choking hazard due to how sticky it is, and corn doesn't have a whole lot of nutritional benefit when it comes to helping her put on some weight.  If you do want to continue trying peanut butter, try spreading it extremely thinly over an unsalted piece of cracker, a cheerio, or even a piece of stale bread.

It sounds like you are correct about her not being pregnant, but the only way to know for sure is to wait the remainder of the 21 day or so gestation period, as some mice do not show very much.  I would hold off on breeding anyone until you are sure there is not an illness being passed around, especially since it is extremely difficult to treat pregnant and nursing mice.

While it doesn't sound like she has a specific disease, it definitely sounds like she is feeling physically or mentally stressed.  Check her environment over very carefully, and watch for other signs of illness that may help point to a specific cause, such as loose, discolored, or bloody stools, clicking when breathing, or sneezing.  Of course, if you can, a vet is always the best option, as they can do diagnostic tests to help determine if anything is going amiss in her digestive system.

I hope she feels better soon, and please let me know if I can be of any more help, or if anything I mentioned needs clarification.

-Tam