third mouse gets attacked

Question
Hello,

I'm writing out of some concern with my mice.  About three months ago I purchased two fancy mice, Regan & Goneril.  They were from the same litter and while Regan tends to be a bit of a bully, they generally get on okay.  Upon reading your suggestion of three mice as the ideal I purchased a third today (after some deliberation).  I named her Cordelia.  She is female as well, quite small, and fairly sedate.  I tried the trick of putting the vanilla extract on all three mice's noses and back ends, and then introduced them.

I watched carefully, and while they were fine on neutral territory, when Cordelia was placed into Goneril & Regan's cage she was harassed by Regan.  There was a small amount of blood, and then they seemed to calm down.  Regan asserted dominance and they were able to coexist peacefully.

Then I introduced Goneril.  Cordelia is very uncomfortable around her, and Goneril will bite her whenever she comes near.  This is strange seeing as Goneril is by far the smaller & less dominant of the two older mice.  However, as long as Cordelia is running on the wheel Goneril seems to be fine with her in the cage -- it is only when she is elsewhere in the cage that it seems to become an issue.  However, I thought they were well enough and just communicating -- I didn't see any blood.  I left for about 30 minutes, came back, and found blood spattered all over their house.  Upon further inspection it appears that this was Cordelia's blood.

I've separated them since, and now Regan & Goneril are in the smaller cage and Cordelia is residing in the large, proper cage.  I'm really worried about what to do, and was wondering if you could provide any suggestions as to how I might assimilate these three together.  If need be I can see if I can find another home for Cordelia, or have them live separately, though that does kind of defeat the purpose of buying a third mouse.  Any suggestions at all will be welcome, and I appreciate your help in advance.

Answer
Dear Kendra,

I'm so sorry the mouse assimilation didn't work out.

Because you introduced them in Goneril's cage, she felt territorial. This may have caused the problem. I often suggest doing it the other way around, or putting them both is a fresh, bleached, clean cage.  Don't blame yourself; apparently I didn't write it in the posts you read.  However, now that Goneril has terrorized Cordelia, I wouldn't try it again for a while.  I'm afraid the three mouse thing just might not work with those three. However, there is one more idea.

If you want to try again, wait a couple of weeks, then put Regan in a cage that Cordelia has been living in for a week.  That way it is completely her territory.  Then put Goneril in two days later.  She will be the outsider.  Observe them very carefully, so Cordelia doesn't have to suffer too much if it isn't going to work.

If you have to keep Cordelia alone, keep the cages very close.  Wire cages are best.  They do communicate in high pitched little squeaks.  I know this because when an only mouse I had (she just couldn't get along with the others but she was an awesome mouse) died, the mice in the nearby cage lost weight, showing they were depressed.  Or you can get Cordelia a friend!  

Later on, if Goneril should die, you can put the other two mice together.  If Regan should die, I'd still try it, putting Goneril in Cordelia's dirty cage.  

Best of luck to all!

squeaks n giggles,

Natasha