There is nothing wrong about feeding pinky rats, or any rat of an appropriate size for any corn snake as long as you are aware that too much can cause obesity. All of my corns get rats as special treats (except for the one or two that don't like them), and I prefer to use them on those that need the extra boost, such as females that just laid a clutch of eggs. Live pinky rats are my personal choice for the snake that has gone off food for one reason or another, but only if the snake is large enough to take them. For a corn snake the size of the one you are concerned about in this thread, even the smallest pinky rat would be too large and would most likely end up causing a regurge. But one it has gotten back on track and grown large enough to take prey that size, alternating feedings with mice and rats would help the snake gain weight a little quicker. You just have to make sure the exercise is there to ensure muscle growth. And I still wouldn't feed more frequently than once a week with the occasional 5-6 day period between feedings. Every time I try to increase frequency of feedings for a consecutive time frame, I get more frequent refusals and regurges.