Because last year my dogs all lost five pounds or more in six weeks on that food.
Because several of my dogs suffered multiple bouts of colitis while eating that food.
Because they switched their manufacturer to Diamond, and since then my bags bought at the same place at the same time, would sometimes cause a reaction when I opened a new bag, and sometimes not.
Because their first bunch of ingredients has a lot more grains and grain fragments than meats. They added barley, millet, and peas and all my dogs reacted to the change because they did not give us any warning that they were making a serious shift in their formula, and one dog did not recover from the switch on that food.
Because after spending a year trying to diagnose the problems with that one dog, and coming up empty, spending hundreds of dollars, and watching my dogs go from lean to skinny to boney to starving. The simple solution turned out to be switching the food.
Since switching from Canidae -- approximately 1 year, I have not had one case of colits (pools of bloody poop). I was getting this 3-4 times a month regularly with the one dog and several times a year from several of the others.
Most of the customer service from Canidae was horrible, though one person did admit that GSDs and Great Danes are usually the ones that have trouble on the food.
But their all losing 5 or more pounds in a little over a month -- that was like I was feeding them saw dust. I was feeding them more and more food, and they were getting skinnier. I think I got a bad run of ten bags.