I just got three more BP's at work that weigh between 55 and 65G. They were born 1/4/17. I think they are underweight since the female we got in born on 11/2017 weighted 58g upon arrival. I now need to get them to a healthy weight. my BP when i got her was 8 months old and 200G. I would say 200 is normal. I am not an expert by any means.