mice feeding

Question
QUESTION: my mouse has had a liter of 6 babies and they are exactly 2 weeks old today January 22 2011 they are starting to open there eyes and she is now putting the bedding in the entrance of her hideout/nest area is this because she wants to keep them in and i barely ever see her in the nest is this normal

ANSWER: Hi Anne,

Yes, this is perfectly normal behavior.  The babies are at an age where they will start to tunnel out and explore - make sure your cage is escape-proof to tiny babies.  She is in the nest less often because older babies need to eat much less frequently.  Once they have fur, they don't need momma to keep them warm anymore, either.  In the next 7-14 days you should see them start to use the water bottle on their own and eat by themselves - at this point, mom will stop letting them eat altogether and wean them.  Once they are 4-5 weeks old and drinking reliably from the water bottle you can separate out the boy mice.  Remember to keep a close eye on them, as sometimes males can become violent toward one another once they sexually mature.

Congratulations on your new babies!
-Tam

---------- FOLLOW-UP ----------

QUESTION: I kind of figured out why she closed up the entrance i played with them all today because they have just opened there eyes and i tried to put them back and they would stay in the nest the mom couldn't even round them up,but i got worried for nothing and i have two mice together and she gotten pregnant before but she had a miscarriage could she infertile. do you know how to tell if the babies are boys and girls or no but my local pet store said the girls would have visible nipples well if that assumption is true then i have all females and when they first open their can they see or are they still blind for a while

Answer
Hi again,

This is a little difficult for me to read, so if I miss any of your questions just let me know.  First of all, at two weeks old they really do get to be quite the little mischief makers.  It's alright for them to wander around in the cage as long as none can escape from it.  They'll all find their way back to momma when they're hungry.  :)  Just be careful when you change the cage that you don't lose any!

In reference to the two mice who bred and had a miscarriage - if she got pregnant, she is not infertile.  Did she give birth to stillborn pups, live pups who then died, pups that were born too early, or did she never give birth at all?  If she gave birth but they were not alive, something went wrong in utero and I would not risk breeding her again - this sort of thing is very hard on the mother's body and taking the risk again could put her life in danger.  If she gave birth but then the pups died, it may have been that she did not correctly mother them.  Sometimes first-time moms don't have any clue what to do, and sometimes mothering skills just aren't passed on.  If she never had them at all - are you positive she was pregnant?  In any case it doesn't sound good.  Breeding is a very serious hobby, so please learn everything you can before you put a male and female together.  Here are some resources:

http://fancymice.info/
http://www.hiiret.fi/eng/breeding/index.html
http://mouselovers.com/

Sexing the mice gets easier with practice, but it's true that ONLY female mice have nipples.  These are best viewed at about the age they are now, before their coats come completely in.  The best and surest way once nipples are tough to find is by viewing the genitals and the distance between them and the anus.  Here's a guide to determining the sex of your mice:  http://www.thefunmouse.com/info/sexing.cfm

Once mice open their eyes they can see.  They may start hopping around this age, though, so if you handle them be sure they don't have far to fall and don't have anywhere to escape to if they do.

-Tam