Feeding a commercial diet is better than feeding an incorrect raw diet, so if you are happy with Canidae and its working better for you thats great

Your vet is right, if you were feeding primarily chicken it would be causing problems.

A dog can't survive off chicken alone (or mostly chicken) any more than we could survive off the same meal every day. This is why commercial diets are full of so many supplemental ingredients, to round out and balance the diet. But its always better to get the nutrition from the source. Eating your veggies is better for you than taking a vitamin! I feed: chicken, turkey, duck, cornish game hens, pork, beef, lamb, venison, rabbit, and goat as muscle meat/RMBs. For offal I have: turkey hearts, beef hearts, beef tongue (those three are muscle meats as well), chicken gizzards, turkey gizzards, venison lung, beef kidneys, green tripe, pork liver, beef liver, lamb liver, and lamb heart. I think thats all, lol. A pretty rounded diet. I have a chest freezer full of meat in the garage. I probably have around 150 lbs of meat in there right now, and I'm picking up 33 lbs of venison/stag in the next week. Plus whenever there are things on sale or marked down because its on its last day I grab them. I scored 4 perdue all natural roaster chickens yesterday for 99c/lb. Thats not a good price for chickens in general, I usually stock up when they hit 67c/lb but those ones arent all natural without hormones/antibiotics. A friend of mine scooped up a roadkill rabbit for her guys, lol. Thats too much for me, I have a no fur no feathers rule for my own sanity. It was hard enough feeding raw in the beginning since I'm a vegetarian. One time I had to spin around and throw up in the kitchen sink. Its the smell that gets me! (this paragraph is directed towards no one in particular, just educational!)

Before you criticize someone walk a mile in their shoes. That way you'll be a mile from them, and you'll have their shoes.