Bunny was a poor-doer at first, so bringing her home at 2 months old she was 4 lbs.
2 months: 4 lbs
4 months: 9 lbs (when she was sickest with Mange)
6 months: 25 lbs
10 months: 35 lbs (current)
My previous BC was about 30 lbs at 6 months and topped out around 55-60 when she was in shape. She came from a reputable breeder for work Borders, but she was just terribly large.
I suspect Bunny will top out around 45.