The constant rumbling is making me nuts! We have three girls who have been together since we got them at the end of November (and for all I know, they might be from the same litter). There had been some rumbling in the past, mostly Cinnamon bossing the other two around. But lately...holy moly! Marshmallow and Cinnamon are constantly rumbling at each other and at poor Cocoa. No fighting, just the irritated sound. Is it because of their age? They are around 6 or so months right now. Will they grow out of this phase and chill out?