Belle was abandoned by her mom as a baby, so we got her when she was about 3-4 weeks. We kept her in a spare bedroom with a baby gate up. She never whined or anything in there (unless she was hungry ). I was so nervous when we decided to let her roam (she was about 10 weeks by then). I followed her around for a little while, she explored, everything turned out fine. She slept between and hubby for the first few nights. Then we decided to get Katie (we wanted to get a cat around Belle's age) - we went to a shelter and picked her out. She was about 10-11 weeks old. We put the cats together right away (maybe not the best idea, but we didn;t know that at the time). They both had the run of the house - actually they were friends in less than a week. Everything worked out really well