Female mouse putting bedding in her food bowl, not as active

Question
Hi, my name is Emma, I have a female pet mouse called rogue, she is roughly a year and a half old, about 5 days ago my male mouse escaped and managed to get into her cage, she is a lot bigger and older than him and i don't think she would have let him mate with her but I don't know how long he was in there, recently she seems a bit slow and filled her food bowl with bedding to lye on. I am worried she might be ill because she just doesn't seem right to me.
She normally runs riot round her cage which is filled with toys but she hasn't been doing much for the last 30 hours  :(  please help  from Emma, Rogue, and Tanner ( nicknamed Houdini for his escaping)

Answer
Dear Emma,
thank you for your question.
If they did mate, it would be some more time until you can notice any changes in her behaviour I think, but I wouldn't rule it out. Usually, female mice will mate quite readily with a male.
I would recommend a vet visit to rule out any health problems, though, if her behaviour is really that unusual. You can find good rodent vets here:
www.rmca.org/Vets
http://gerbilforum.proboards.com/index.cgi?board=vet
http://www.gerbils.pwp.blueyonder.co.uk/gerbils/vets.htm#UK
If she is in good health and not pregnant, I would also recommend introducing her to at least one other female. Mice are very social and should not be kept alone. Unfortunately, male mice will fight with each other, which makes finding company for them almost impossible unless you have a vet who knows how to neuter them. Here's a good guide to introducing mice to each other:
http://www.allaboutmice.co.uk/introductions/

I hope I was of some help to you
Jennifer