When I rescued my little Tia, she was a mere 2 lbs. Because I was more worried about her well being, it never crossed my mind to worry that one of my 5 at home could hurt her. My others babies range from 6.5 to 15 lbs, but, they have never even snapped at Tia. I got her last Easter, she'll be 2 in a few days, and up to a whopping 3 lbs now and just as happy as she can be. All my babies love each other!
I say give it a shot. If it doesn't work, she would make a perfect playmate for Tia!
