underweight itchy GSD

Question
My daughter GSD 2 1/2 yo neutered male is extremely thin. He has been checked out by her vet and declared healthy but underweight. She was feeding him the high protein dog foods to try and increase his weight but he is not a big eater.He then starting scratching incesstantly,(again vet checked, no issues found)He is a high energy dog. Any suggestions for the itching and to increase weight.He should be at least 70 lbs and is only 62. Thanks

Answer
If his ribs only show a little, and he didn't itch on the old chow, you might go back to it.  It is common for Shepherds to keep themselves on the thin side.  If it isn't too bad, you may be better leaving well enough alone.  

You could also focus on the calories, not the protein in the food.  You may be able to find the calories in a food on the company's website or by calling customer service.  Puppy chows often have more calories as well as working dog food.  Feeding a higher calorie food could result in him eating less too.