A lot of mainstream pet food companies (FourStarBall could name them -- Puritana is one I think.....) are notorious for the foul practises in their companies. Not to mention the illegal chemicals and bits of mashed-up, diseased animals they include in their food, they're also quite happy to let on-display animals starve to death, or die of diseases because they rarely got their cages/whatever cleaned out.

It is the reason we get all our stuff from a local Pet Warehouse that only deals in proper animal food and refrains from anything that's associated with the inhumane treatment of animals.