Hmmm....I wonder if Jackie is a light weight then. She just turned six months last week and she is 29 pounds. Her parents weighed between 50 and 55lbs so I guess she is on target for her age. Jackie and Max could pass for siblings though with their coloring.
Right now with Beau at 6 months, he weighs 45lbs. While at 8 months, Bella weighs 41lbs. Bella's parents were HUGE!, somewhere around 85-90 if I remember correctly. But we don't about Beau's parents since we adopted him.