I have two female guinea pigs who live in the same cage they are about 11 weeks old now and are getting along well as they werent from the same litter. But my brother has got another female guinea pig which was in the same litter as 1 of my piggies but she lives on her own. He doesnt take her out all that much but she does run around with my piggies for about an hour almost every evening. My brother doesnt want another piggie but I'm just worried shes going to be very lonely as she usually cries for a little bit when she is seperated from my two after their run around.