Rat aggression?

[t3h_kyle]

Hey everyone,
I have 4 female rats; 2 pairs of 2 different litter sister rats.
I've noticed recently that one of my rats is acting rather aggressive towards the other pair of sister rats. Ive noticed she's an ear biter as they have some blood on their ears and one in particular has barbering and cuts on her lips/face.. they have lived together for some time now (~3/4 of a year) and both are closing in on the one year old mark. Introductions were good and this is behavior has just happened only recently. They were living together fine before. Just want some advice on maybe what to do, they're all lovely and nice towards me and I want the best for them.
Thanks everyone.

 

[lilspaz68]

Forget the barbering, and cuts on the face could be from trying to get away from an aggressive cagemate. How does she act with them? Have you seen the bullying? Chasing?

 

[jorats]

First thing I would do is a mite/lice treatment.

 

[t3h_kyle]

Oddly enough the one with the cuts on the face is the instigator.. she tends to run up to the one whom is a little bossy a lot. I feel as if it's out of annoyance or something.

 

[jorats]

That makes sense, often times, a rat will run up to another rat, get in its face and the other rat will bite or scratch face. But if this behaviour is new, I would still do a mite treatment. Mites are so common and will make any rat grumpy.