Can you see it? I realize that in the second picture he's wet and it's also getting dark, but after only five days Corny already looks slimmer to me. He hasn't quite reached will-o-the-wisp size , and we haven't given him the new nickname of "Tiny" yet; but the guy's smaller!
I've worked him walk/trot/canter (just a little of the last) on the longe line in the arena every day, with the time being increased from an initial twenty minutes up to thirty minutes. We take a brisk walk up and down the hills around the pond afterwards, so he's out and about for a total of around an hour. I also rode him for half an hour on Sunday. This exercise, plus getting exactly half of his former rations seems to be doing the trick. He's still got a ways to go, but I'm relieved that he's showing progress so quickly. He, not surprisingly, is much less enthusiastic about all this than I am, but he's being a pretty good sport. And he's looking forward to being called "Tiny" in the very near future.
As for Sarah; the vet comes out tomorrow to check her over. Please keep a good thought.