Hair loss, mouse mites?

Question
HI, im hoping you can help me as my vet didnt seem to be able to. I have 2 mice both females, I bought them from and exotic pet shop about 12 weeks ago but for the last month one of my mice has lost some hair around her nose and she is cleaning herself and scratchin mainly in the same place. I took her to the vet when i first noticed her losin her fur and the vet is treating her for mites with xeno 50, but my other mouse is fine and i havent noticed any hair loss on her, i had used wood shavings for over a month before this started happening but have now stopped using it just incase she was allergic to it, but she is still slightly bald around her nose which isnt as bad as it was but it doesnt seem to be getting much better can you give me any idea please as what could be wrong because i dont hink it mites, the food im currently giving them is wagg hamster, gerbil and mice food and ive been taking out the peanuts for a couple of weeks and also the sunflower seeds would a Rat food be better for them, both mice are eating well so im stumped... also i noticed the other nite (im sure its the balding one) the noise she was making sounded like a baby bird chirping, is this normal??
Please I hope you can help me & Thanks in advance.

Answer
Dear Kel,

The vet should be able to examine a skin flake under the microscope to identify the problem.  If it is mites, the problem is that both mice need to be treated.  The healthy mouse is giving the other mouse the mites as fast as she is being treated.  Mites are a little like germs in that if you are really healthy they don't make you sick, but if you are a little run down for any reason, they can make you sick.  This is why you don't see evidence of mites on the healthy mouse.

When the mice have been treated they need a very clean cage with everything washed well, and paper or wooden items thrown away.  If they are treated more than once, the same should be done every time.  

If nothing has changed in the cage over the past year then it is doubtful that she has allergies to the litter or food.

Best of health to the mouse!

squeaks,

Natasha