Maybe its just the transition from the shelter to your home. How long have you had him?
I would pick up an oatmeal bath and see if that gives him some relief and try it on Monday.
The shelter wasnt likely feeding wellness so perhaps he just needs the time to get used to the good food. It may take a few weeks for you to notice any difference. Maybe you could pick up some fish oils and see if that helps. Go easy at first because you dont want to give him loose stools!
Also if he was an outdoor dog before you got him it may take time for his body to adjust to not having to be in the various elements...???
How about a picture of your new addition?
Tabitha April 10, 1995 - August 23, 2013
Bomber April 10, 1995 - July 12, 2010
Winston Nov 15, 1999 - September 15, 2011
Sophie Aug 30, 2011
"UNTIL ONE HAS LOVED AN ANIMAL, PART OF THEIR SOUL REMAINS UNAWAKENED"
He is your friend, your partner, your defender, your dog. You are his life, his love, his leader. He will be yours, faithful and true, to the last beat of his heart. You owe it to him to be worthy of such devotion.