Your new baby is absolutely adorable! As for your question...I was told it depends on the person training them and the dog themselves on what they perfer. Zeta tried the "pen" and hated it! She wimpered the entire time she was in there like she felt she was always in time out or something...I couldn't do it anymore. So, we got her a small metal crate (big enough for her to lay around or play in with her toys) and she loved it. She doesn't mind going in when it is time! I would say it mainly depends on you training your baby to use it. I wish I could give you more help but that was our experience.