Unhealthy Dog Food

I heard somewhere once, "if you love your dog, then never give them something you are not willing to try" Sounds like good advice.
We are on our 3rd, different kind of dog food. The first was this organic food from Costco, not made by and we had no problems with it. Until they decided out of the blue to not sell it anymore. We then tried the Kirkland's Chicken and rice food. We did gradually changed him over to it. But this gave Boogie running poop, so then we tried Iams. He got a horrible rash and has lost his fur on his sides. I did some research into Iams and discovered that I am not alone, Iams is to blame for a lot of dogs skin problems and in fact is rated at 0 out of a 5. http://www.dogfoodscoop.com/dog-food-comparison.html
I was surprised to discover this as I normally have a lot of confidence in the products that Costco sells. Especially since it was the higher end in the pricing scale.
So now I have stopped giving him Iams cold turkey, am trying the Kirkland brand Lamb and rice. I am giving it to him gradually, but am also giving him homemade food for now. He is one lucky dog.
I am hoping that his rash and hair loss improves, if not I will have to take him into the vet and be charged over $100 for something that doesn't need to cost that much. The good news is that I really haven't seen him biting at himself. So, hopefully the new food is helping already.
Oh and I really am not going to try his food, just can't bring myself to do that. I tried to get the kids to, but they won't either. Oh well.