female aggression

Question
hi there, please help, we brought two female guinea pigs back in july, they were from our local pets at home, living in a big all female group of around 20 piggies, aged 11 weeks, we had done alot of research on the Internet and brought a large 3 tier cavie condo, they were fine, settled in great.
about a month ago ( mid September) we noticed that one of our females (toffee) had been spending more and more time in the middle section of the hutch, even sleeping there alone, which was a real concern, we have had them indoors now for 2 weeks as we are wintering them over inside with us, and have noticed a very disturbing change in our other females behavior (coco)she is very aggressive to toffee fluffing her hair grrrrr noises, swaying her hips, charging at toffee etc.... the affection they had for each other has gone, coco just will not tolerate anything to do with toffee, toffee never retaliates and is being bullied like this all the time.
why would coco who was very bonded with toffee,  now after a couple of months hate toffee so much, should i separate them permanently? please help as i don't know what to do for the best, i will try anything if it will help them.
kind regards
Nikki

Answer
Easy! My guinea pigs used to do the same thing, friends to foes to fight to friends to foes etc...
I am afraid there is not much you can do except wait it out and separate them temporarily with supervised play time together. Either put a divider in the cage or buy a new one, depending on the type of cage you have. It is a dominance thing and they must get over themselves. Also because they are very young you should expect this for a while. Make sure that they are safe, this is number one on the importance scale.
Feel free to write back


Thanks for asking!
-Nicky