Going by your logic, having a heat pad under the cage isn't "natural" so you might as well take that out. Dead prey IS natural because the snakes we have are captive animals so we have to provide their needs (safety and comfort) as best we can. We can never truly simulate nature and feeding live prey is a sorry attempt to do so. The only reason to feed live in my opinion is when your snake will not eat anything else and you have tried for a LONG time to switch it over to dead prey but it won't, so you feed it live to keep the snake alive. No other reason is good enough.