I rehomed a couple of 3 year old female sister guinea pigs today from someone who was unable to look after them anymore. They seemed to get on well together during the time I saw them where they were and I let them calm down and rest after the short journey and tried to introduce them to my two females (One is 1 and the other is about 4 months who got on really well.) The smaller of the two new ones got on really well with my two but the bigger of the two started with the teeth chattering, standing proud and caused a bit of a squabble between with my eldest. I seperated them and the little one calmed down and my two went back about their daily business but the larger of the new ones was still showing signs of aggression, even toward her sister who was cowering in the corner. I've taken angry pig and put her in my hospital cage away from the others and the small new pig went and made friends with my two instantly. Is this normal behaviour and will it settle when she has gotten used to the change or is she likely to be a grumpy solitary piggie? The run she is now in is huge as I built it myself and the cage they were both in before was tiny. Is she a bit lost and freightened and aggression is a coping mechanism? Any help would be greatly appreciated as I would love a happy piggie pen.