The "Rib Cage Test" for Weight
Look at your dog from the side. Her tummy needs to tuck up from her chest and not be level with or hang below her chest. If you can easily see a dog’s ribs, she’s probably underweight. But in some breeds, including Greyhounds, Whippets, and Italian Greyhounds, the dog’s ribs show at a normal weight.
Breeds with heavy coats need closer scrutiny because
you probably can’t see ribs even when the dog is underweight, so try the next two steps for a more complete assessment.
Look at your dog from above.
As you stand over her and look down, your dog needs to have a visibly tucked-in waist, but her hipbones shouldn’t protrude too severely. If your dog looks like a barrel, a sausage, or a small beach ball with legs, she’s probably overweight. If her hips protrude sharply, she’s probably underweight. If she has a nice curve inward at the waist, she’s probably at a good weight.
Feel your dog’s sides for the ribs.
This test is especially important for heavily coated dogs, whose fur often conceals weight issues. If you can feel no evidence that your dog possesses a rib cage, she’s probably overweight.
If you can feel the ribs but they have a slight padding, like a light blanket over them, then your dog may be just right. If the ribs are obvious and feel like they’re covered with only the thinnest layer of skin, your dog may be underweight.