Got 1 guinea pig in July, got 2 more in October, they are all girls, Millie the first one is just over 6 months and the Twinea Pigs, Lillie and Gwenie, are just over 3 months, they are all sisters, same mom same dad. We bought the 2' x 6' pen with a lid and I love it. My pigs have room they have houses and toys and 2 big metal feeding bowls. I am so happy with the ease of setup and the ease in cleaning of the cage that I bought. Thank you for the great info that this site provides. I have owned pet rats before and have found that the noises that rats make does not compare to the chirps, squeals, squeaks, and whoot whoots that my pigs express. Love Guinea Pigs.