orphaned baby mouse getting bloated

Question
I've been taking care of an orphaned mouse for 10 days now..he was probably 2 days old at the most when he was washed-up on our patio after a storm...he was having very regular bowel movements with a wet-q-tip stimulating his belly and privates..but now it is less productive than before and it seems as if he is getting bloated.  He is on diluted human soy formula.  any help is appreciated.  also, is it too late to switch him to kitten formula as I hear this is better?

Answer
NEW INFO:

Dear Julie,

The previous mouse expert that I contacted wrote to me:

"It is not too late to switch formula, however it could make him constipated in the process, and if he's already having tummy troubles I would wait a bit. How bloated is his stomach exactly? There is a condition called megacolon that can affect rats and mice, that usually shows up around this age. How old is he exactly? Knowing this will help me decide what steps should be taken next with this little guy.  Also, if the owner can get some possum milk replacer that is what's best for small mammals. If they live where exotics are allowed they may be able to buy it from a pet store nearby."

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Have his eyes opened? If not, you are probably right about his age. Can you try to get the possum milk replacer? I found it online:

http://www.sugar-gliders.com/possum-milk-replacer.htm

You would want to have it arrive as quickly as possible of course.

It is possible to post a photo with your question here. Maybe that would help her determine how bad the problem is. I can give her my password so she can look at it. Or you can send me a photo at mouse@lovemouse.com. Is the problem getting worse? Or perhaps better? Have you gotten advice from anyone else?

squeaks,
Natasha