Hi Martha-
No there is no one recommended food for a dog that scratches. Mainly because the reasons for the scratching are different with each dog and some have nothing to do with food at all. You may want to discuss the scratching with your vet and talk about determining what the cause is. I would personally be weary of mail in hair and saliva tests for food allergies. They are notoriously inaccurate.
Also wanted to note that it seems that the Glacier Peak test is still unavailable for resale. Been like this for a few months now I believe.
