Ideal weight for my dog

We've got 3 dogs and my inlaws have got 5. They are all from the Labrador family but this batch was fathered by a Lab of questionable bloodline, so they are no longer pure Labs. Still, they are all adorable and loyal dogs.

Now, the issue of the weight of my dogs has been bugging me because each time bro in law and his wife come round, they say "Your dogs are thin, especially Benjie. He's all bones!" Then when mom in law comes by, she says the same thing. I suspect she's just repeating what she heard from them since she's not that much of an animal lover and has precious little time to spend with the dogs anyway. She wouldn't know any of their habits.

True, Benjie is on the lean side. Queenie is a real food hog and she is the biggest, while Bonnie has the slightest build but for her petite size, she looks quite filled out. Benjie is tall and gangly, with a straight arrow tail. His appetite used to be really poor when he first came to us (all 3 were first raised by bro in law by the way). My maid and I had to persuade him to finish his food, and even hand feed him. But the last 2 months has seen a marked improvement in his appetite and he always finishes his food now, even ahead of greedy Queenie.

Back to the thin part. With all those thin remarks, I did some reading on the net and the general consensus out there is that Labs should not be overweight. When patting a Lab, you should be able to see his last 2 ribs and definitely when stroking the dog, be able to feel his ribs without having to press down hard to feel for them. That puts my dogs in the acceptable weight category. My inlaws dogs on the other hand would be fat! Waddling walk, and no ribs to be felt. I know. I checked.

I wonder how many people use Hill's Science Plan dog biscuits for their dogs. My 3 were raised on them, but Benjie just hates it. So I've switched to Fides (Belgium) and Top Ration (US). I intend to try Propac next.