Missing tail

Question
I have three female mice and have had them for about 5-6 months. I came home tonight, and one only has about an inch or so left on her tail and the other had a bloody nose. My third seems to be okay though. I'm hoping that they got in a fight and that they are not sick- although fighting is not good either. They are running on the wheel and eating fine. Should I separate them or just leave them be? I read it is not good to leave one alone, but I don't want them to hurt each other anymore.

Answer
This is definitely not normal behavior, I understand your concern about separating them. It would be your decision whether or not you keep them together. It seems strange they have been getting along for 5-6 months and this suddenly happens. It is also unusual for females to fight.

I don't believe it is a disease (it is understandable to think its a flesh-eating disease if you've seen too many horror films). The give-away is the mouse with blood on her nose. Perhaps if you have changed something about their environment, e.g moved them to a smaller cage or changed their diet may be cause for the fight.

Maybe if you gave them yoghurt or some other liquid food she got some on her tail and the other thought it was food (this is unlikely).

Please feel free to ask any more questions.