Had to separate my girls

[Chrisdon23]

I have 2 females; the first is just over 7 years old and the second is about 3 and a half. They’ve always been in the same cage, (about 8 sq feet), and have gotten along well. A couple of weeks ago, we noticed that the younger one has started barbering the back end of the senior one — I don’t believe she’s hurting her or anything but the senior one has never been big on other pigs touching her so she whines and squeals when the younger one touches her. We’ve put a temporary wall in their cage so they can still see each other but I feel really bad because now they’re each only left with 4 sq feet. (We also have a large
hutch for our bunny so there’s no room for anything else). The senior one seems pretty happy to not be pestered anymore but the younger one hates it I think.

Is there anything I can put on the fur of the senior one that will make the younger one leave her alone? We’ve tried putting them back together a few times but the younger one just seems determined to barber the other one so far.

[Lynx]

From the guide on the hair loss page:
https://www.guinealynx.info/hairloss.html#barbering

Barbering
Although they may have all the hay they want, no lack of nutrients, and ample space to move about, some guinea pigs are bound and determined to chew on the hair of their cage mates. Apart from isolating the industrious guinea pig, there is little that can be done to effectively curb this behavior. Application of "bitter apple" is claimed by some to work, but others just accept having a "designer pig" or provide private living quarters for the offender. If you are not showing your guinea pigs, this should not be a very serious concern.

Check over the younger one for any changes in health. I imagine you have lots of good quality hay around, no? I think there have been one or two guinea pigs that (perhaps from self grooming or barbering) developed a hairball (rare).

What are your temperatures like? How long is the hair on the older guinea pig?

[Chrisdon23]

I have a really good source for Timothy hay and buy it by the bale so they always have a large pile available. They always have a chew stick or two and a Timothy hay ball with a bell to play with. The younger one hasn’t lost any weight and seems as spunky as always. Their cage is right in our living room which is usually kept around 20-22 deg Celsius. The older one has longer hair.

[TeddyGram]

I’m newer to guinea pigs so this is a a true guess or thought that experienced gp people could comment on: Would the older pig’s aging possibly signal to the younger pig that she has a shot at being dominant pig? Teddy started barbering me after his first illness. I was trying to understand it in terms of gp communication.

[PooksiedAnimals]

Absolutely illness or age can change the social dynamics. It's why I tell people who suddenly have a change in dominance in an established pair for no apparent reason to check if both guinea pigs are healthy.

[Chrisdon23]

Happy to report that they have been back in the same cage for a few weeks now with no issues!

[Lynx]

Thanks for the update!

[Sef]

Hey, that's good news! Wonder what that was all about?