Hi, had my 2 guinea pigs (sows-9weeks) for 2 weeks now, and I'm concerned that they don't get on! They were living together when I got them, so were put straight in the hutch together. They seem ok, but sometimes I notice the larger one kind of purrs in an aggressive way to the other one if she goes near her sometimes. They also chase each other around a lot, but to me it doesn't look like it's in a playful way. Is this normal? Thank you!