I've never been able to understand why people who think about GMOs, certified organic produce, free-range eggs--people who drive Priuses, use canvas shopping bags (ours are made of something like Tyvek), recycle, and have programmable thermostats, will think nothing of feeding their pets Purina.
I'm talking mostly about dogs and cats, of course. But the same is true for most other pets: why do people feed generally-species-inappropriate diets?
You don't see wolves at the zoo being fed kibble, which should, in my opinion, ring a few bells--if wolves are, essentially, wild dogs, then why shouldn't they be fed kibble? If they're not, could it be because kibble isn't actually a good food for dogs? And ditto for cats, and tigers.
Links here and here deal with raw diets for cats and dogs--it's all been written, and I'm not going to go into the supposed benefits for them, in part because I myself do not believe many of the claims. I do believe that raw diets have dental benefits--Shadow's teeth are still as pearly white as they were the day I got her--and that they are healthy and at least as good as if not better than prepared foods, when done right. I do not believe that a raw diet will cure diseases such as renal failure, although I do believe that they can mitigate the effects for quite a while. I am skeptical of claims that it helps mitigate behavioral problems, but willing to give the benefit of the doubt in most cases--but not because of "toxins" or any of that crap. I do not believe that feeding a raw diet is without risk--for me, with my biochemistry background, it's pretty much a practical application of my undergraduate degree, but for others, who have not bothered to look up things like the urea cycle online, it can be difficult to separate the information from the misinformation out there.
But I do believe that feeding a species-appropriate diet, or as close to it as one can get, is, in fact, what is best for one's pet. We humans have come a long way since the days "food safety" meant "let the other monkey eat those berries first", so it's hard to say exactly what a "natural" diet is for us. This is not to disparage the modern diet--nutritious and plentiful--but to point out that for humans, culture and environment are far more important dictators of what we eat than they are for animals, who not only are completely dependent upon their environment for their food, but also cannot be said to have any culture.
Pet food companies make a killing out of selling "Natural" stuff, but if you look at the ingredients' list, well--good luck finding any of that stuff outside of a chemistry plant. Some of the better companies actually do sell pet foods made of meat--and I don't want to know how much that costs, especially when the cost of adding one portion of meat to the weekly grocery list is so low.
That's the other thing: feeding a raw diet doesn't have to take a lot of money. It can, if you like buying those hamburger patties filled with "wholesome goodness". But my cats get mostly chicken, or whatever's cheap that week, and a bit of canned food if the drumstick is unusually small. It works out to about 1 euro/day to feed them, which is actually less than feeding them a brand name cat food.
If done properly, I do believe that feeding a raw diet is better than any brand of dog or cat food out there. Going natural, for them, makes as much sense as it does for you.
Disclaimer: I do not make any money from any of the pet food websites that I have linked to. They are merely the most prevalent brands that I can think of, and most likely to be universally available.