I use to feed mine Canidae as well. But then they switched their formula and now it's crap. Canidae does contain ethoxyquin.
I noticed a big difference once I took them off of this food.
I switched mine to Life's Abundance and they do great on it and they love it!! Plus the kibble is small and the price isn't bad.
I also tried them on Blue Buffalo and they loved it but they started getting overweight on it so I switched.
I do want to mention you might want to be careful with the grain free foods. They usually have a much higher protein which isn't very good for this breed due to their small livers and liver shunt being so prominent in the breed.