Aggressive Cagemate and Newborn Pups?

[rbrb3373]

Hey everyone! New to the form, and I have a bit of an urgent question.
I adopted two female pigs 2 1/2 months ago knowing that one of them was pregnant. They were 4 and 2 months at the time of adoption, and the older one was the pregnant one.
Fast forward to last night and she had four healthy pups! Both mom and babies are eating, drinking/nursing, and doing well. However, the cagemate does not seem to be adjusting well.
They are in a 2x4 C&C cage with a large loft, so it is a little crowded with the babies but I have plans to expand and partition the cage so there is a.) space for everyone and b.) separate spaces for male and female pigs (because yes, I am in fact keeping them all haha).
Today the younger pig was mounting the older one. I triple checked and she is 100% female, so I'm guessing it's a dominance thing. She has also begun to be aggressive towards the pups. I watched her for while and left her with them when it was minimal aggression, but then she LUNGED at one of the babies so I removed her. I am not leaving her with the pups overnight, but I also do not want her to be without a casemate for an extended period of time.
Any advice? Is this normal? For what I've read and been told auntie pigs are typically great with pups. How should I handle this?

 

[bpatters]

The cage is WAY too small for that many guinea pigs. I wouldn't put her back in there until I'd expanded it. If you've got the room, you could take the loft off and use it to expand the main cage.

In the meantime, maybe you can house the one right next to the mom and pups.

 

[Soecara]

Guinea pigs usually are great aunties, but the key word there is usually as there are occasionally exceptions. For now I would keep cranky aunt separate, give it until at least when the male pups need to be separated and you have expanded the cage before trying re-introductions.

How many male pups do you think you have? Depending on the answer to this you may need to re-think the potential caging plan. If you aren't sure you can first try feeling just above their genitals, male guinea pigs have a bone in their penis which you can feel just below the skin above their genitals. Also this website has some images to compare to https://www.cavyspirit.com/sexing.htm