I'm not so sure about these vets! The first time I took Riley in for a visit she about 8 wks & weighed about 1 lb 4oz. The vet looked at her & said "She'll probably be about 10 lbs. She's full grown & weighs 3 lbs 8oz. I wouldn't put to much stock in the vet. Look at the parents & earlier litters to give you a better idea.