I've been feeding the same salmon and sweet potato formula from Costco for about 6+ months with no issues. Actually, we have even better coat condition! I find it to be a quality grain free food at a good price and it suits the Basenjis and Ridgebacks well.
Our foster girl has lost weight on this formula and her coat is improving, while the other foster boy (who became a permanent pack member!) has gained some weight he needs. He was a dog that would not eat kibble, and he loves this formula. (Once I tried the turkey version and he refused to eat it!)
A win-win in our household. No itchies at all. Have your dogs recently got new beds or anything different? Did you mow the lawn and stir up bugs? I'd try adding a fish oil capsule to the mix - just my two cents!
Good luck Lib! Hugs to the hounds…
Jennifer