[Britster]

With them being 3lbs at 17 weeks old... it doesn't seem like 5lbs and 7lbs as adults is that far of a stretch? But if the vet says they are overweight... it's hard to say without pictures. You should be able to feel the ribs easily without pushing hard and see a waistline.

Also, 1/4 cup per day sounds about right for their size. But you say you "watch" how much they eat. Are they free-fed? I would just up their exercise and do scheduled feedings so you know exactly what they should be at.