What dimensions should I make my guinea pig cozies? I want them to fit two female guinea pigs. They're only a few months old right now, but I want to have the dimensions still fit them when they are adults. I was looking on ebay, and I saw one that had a 13'' wide x 15'' deep cozy. Would this be too big for a pair of 2 female adult guinea pigs, just enough, or should I aim for something bigger/smaller?