Mouse introduction goes wrong

Question
Dear Natasha,

I did abit of research on introducing mice and followed the general advice (clean cage, swapping bedding before introduction, neutral territory, vanilla on the bum etc etc.)

I have 2 adult female mice and am trying to introduce a third juvenile female. I introduced the less dominant of the two adults, and she has taken to the 'baby' fine, but my dominant adult is causing hassles.

I separated them on the first introduction because she was getting too aggressive. I tried to introduce her again a few hours later and unfortunately she drew blood by nipping the baby's tail just above the rump.

All the info. I've read has said I should separate them , but not much more... should I try again? Should I wait a little longer until the juvenile has grown abit more? Do you have any other advice?

All the best
Trace

Answer
Dear Trace,

There is one other thing I would try.  Keep the less dominant female with the new mouse.  Don't clean their cage at all for two weeks.  Then put the aggressive mouse in with the others.  No vanilla this time.  We want the aggressive mouse to have the disadvantage of being on someone else's turf.  

The disadvantage of this method is that the aggressive mouse is used to living with a friend, and she will have to live alone for two weeks.  Put the cages right next to each other so they can still communicate (they squeak to each other all the time, we just can't hear it).  Give her lots of extra love to make up for it-- an hour a day if you can.  One mistake people make is blaming an aggressive mouse for her behavior and feeling it is ok if she gets punished.  She's just being a wonderful little mouse the only way she knows how.  

This is your last hope.  If they still fight to blood, you will need two cages.  However, no mouse should live alone!  If you can, keep the two original mice together because the aggressive mouse might never take to a new friend, and get a new friend for the newest mouse.  Still keep the cages near each other.  The optimum number of mice in a cage is three, as you were trying to do, but I doubt you want 6 mice, so this way, at least when one dies the other will have friends to talk to until you do something else (it will depend on who is left).  

Best of luck!  Do let me know what happens.  

squeaks n giggles,

Natasha