Did you have any results from bloodtests, our dog completely licked all the hair from the back of his frontlegs and we thought he was bored because he was blind, we found out he had low thyroid.
I gave him 1 drop of Lugol'sIodine every day and his hair came all back.
You can read about Iodine on the Iodine supplementation forum.
We just got a new rescue dog and we switched him to Innova food. I had researched this several years ago and had switched my old dog on this food too.