I have two cockatiels, Desiree, who has been adopted from a negligent household and is not very friendly, and Clytemnestra, who has been hand trained and is very sweet and affectionate. I feel bad for her because when she tries to socialize with Desiree, the reception is cold and she just wants to hang out. We play with the birds a couple of hours a day at least, but I still see Clytemnestra trying to play with Desiree with no success. I built the cage myself and it's extremely large, and I would be interested in getting a third bird. I was wondering whether it would be an option to bring a parrotlet into the bird household or whether they wouldn't socialize well. Desiree is relatively ambivalent about Clytemnestra unless the latter tries to engage her, so I don't think she will be too upset by the new addition, perhaps just slightly annoyed. Is it alright to get a similarly sized bird of a different species?