Is this anything to worry about??

[Cookie]

So lately my two chinchillas are acting differently towards each other, for the most part they still sleep all smooshed together but every now and then they chase each other and make this sound (its "the defence sound")
http://www.chinchilla-sounds.de/bedr_e.htm
They do this at least once or twice a week, maybe more if it's when I'm not in my bedroom. I've had them since the beginning of december 2010 and right now they are 9.5 months and 6 months (sisters). The youngest one has been quite crazy lately, I'm guessing thats the "terrible two's" people have been talking about??...she quite often reminds me of taz the tazmanian devil from those bugs bunny cartoons LOL.
Lately I've noticed her whiskers have been kinda broken/chewed(?) and her hair sometimes comes out in little tufts, but the hair coming out has happened ever since I've gotten them (just a little sidenote, do you think she might have some sort of fungus or something? I havn't seen anything on her skin but even when I don't handle her she still has small tufts of hair coming out)
So I'm just wondering if they are having a little battle over who's "boss" or if they are going to fight and I should just seperate them before one gets hurt? I'd like to keep them together so they have company but I have an fn 142 so seperating would also be easy.
Thanks

 

[GorillaJTA]

The chewed whiskers are being chewed by the other chin as a sign of dominance, and the hair slips could be from their spats.
My boys are about the same age difference and the younger (smaller) one is dominant strangely enough. They still huff at each other and chatter over food after a year. Keep an eye on the spats as they can turn dangerous quickly.

 

[Cookie]

ya, the older one was dominant but I think the younger one is trying to "take over" so to speak and maybe thats whats causing the problems? I'll keep an eye on them...and so will my dog since were all in my bedroom at night haha and she always lets me know when they start to have a spat lol

 

[Cuddlebug]

Your dog is a chinnie fight alarm, that's funny. Keep a close eye on them. If the chasing gets worse and you start to see a lot of hair fulling, or biting, that would be the time to separate them