My kitty threw up his Nature's Variety Raw duck about an hour after eating it. He has eaten this many times, I've been rotating this, chicken, and beef. He's never had problems with any of them, in fact, this is the first time he's ever thrown up at all. This did happen to be a new bag, but my other kitty ate it too and is fine. He seems completely normal, otherwise. Do you think it was just a fluke?