My german shephard is too skinny

Question
I am concerned regarding my2 year old german shephard dogs weight.He was a rescue dog and we brought him home in June.He has been checked throughly by a vet who cant find any medical reason for this. He has been castrated. When we got him you could visibly see his ribs and although he has put on some weight you can still feel his spine. I have had a german shephard bitch before and never had a problem with her weight. He also mults terribly even though I groom him daily.
I hope you can help us,

Kind regards,

Jeminy Jackson

Answer
Hi,  Has he had his stools checked for parasites?  Also was blood work done to check his thyroid or for diabetes?  both of these problems are very prominent in GSDs and will cause them to not gain weight.  If he is from american lineage, you can also see problems with weight gain due to some lines being very lean lines.  GSDs shed constantly and if he is not in the best of health (due to his weight), he will shed even more.  Hope this helps,

Dawn