weight of puppy

Question
i am worried for my 7 months old German shepherd dog as he only weighs 21 kg -- is he weak?

Answer
That may be on the small side.  Have you been feeding it a dog or puppy chow?  If it is too thin, you need to offer it more food.  Switching to an adult chow for the larger breeds at 4 months, slows growth and helps develop sturdier joints.

Your dog definitely should be narrower at the waist than the hips and chest. You should be able to easily feel the ribs, but not see them. Each dog is different. Standard recommendations are a good place to start, but each dog must have its food and exercise adjusted to its individual needs. Here is a link to a good illustrated guide, http://www.longliveyourdog.com/twoplus/RateYourDog.aspx

Some dogs turn out small for their breed.