Go study :
H. Kasstrom. Nutrition, weight gain and development of hip dysplasia. An experimental investigation in growing dogs with special reference to the effect of feeding intensity. Acta Radiol Suppl (Stockh), 1975;135-79.
According to this study dogs of 222 GSDs showed a correlation between HD at one year and weight at 60 days of age. The heavier pups at 2 mo of age had higher incidence of HD. 100 of the puppies were dysplastic at one year and their mean weight at 2 mo was 14 lb, while 112diagnosed as normal at 2 mo of age had a mean weight of 13 lb. This is a significant difference just in this small amount of weight change. Dysplastic males in this study averaged 14.5 lb compared to hips normal males who averaged 13.4 lb.HD females averaged 13.8lb and normal were 12.3 lb. These particular weights do not apply to all GSD dogs but serve as a comparative example. There is a chart from this study which is in Fred Lanting's book on HD ( which I am selling on my website with almopst 0 profit in order for people to learn this
) which deals with weights of pups in 12 weeks between 6 - 20 kg
The 6 kg pups had 44% bad hips in one year and 20 kg pups had 70% bad hips. This could be applicable to litters with average size of pups bigger and smaller.
This is why I am recommending above such weights at the age of 12 or 13 weeks.
Thus I do not think that to ask about weight of the pup at certain age is a "retarded question" .