Dr Randy Huenefeld works on Shaun.
"No more weird trot, no more straight left leg at the canter, and more exuberance than I've ever seen.
"His tail was flying like a flag, and I was hooting and jumping up and down like a mad woman!"
Shaun, who raced under the name Cusack, was rescued from kill pens in Washington state in May thanks to the generous contribution of Horsetalk readers.
He was trucked halfway across the United State to Deb's Kansas farm, where he is enjoying life with his new paddock mates.
Deb recounted how she let Shaun and the other horses loose from a small pasture, where she had hoped they would seek cover in the shelter during cold rain.
"They tend to hang out with the next-door Morgans about 20 acres away. I opened it up this morning after breakfast and Shaun took off like ... a racehorse. Exploded, joyfully sprinting to the other end of the property."
She says she is now going to make chiropractic adjustments a regular thing for her herd.
"The difference is huge. Huge!"
Deb had made the decision to take Shaun for chiropractic because, despite putting on some good weight, he was still a bit crooked.
They drove across the state line into Missouri to visit Dr Randy Huenefeld in Kansas City.
"He said he looked good, although he really needed adjusting. He said he may be so used to moving to compensate for his injury, it has become a habit.
"Everything inside was moving well, so it's just a matter of him trusting his body.
"I have no idea what kind of environment Shaun was in before the kill pen. He may have had a pretty restricted space, and I know he went without dinner more than a few times.
"We'll never know what happened to this great horse, but now that he's able to move freely, his body is responding well and I have a lot of hope for him.
"I've even began to think about riding him, and that was not in the picture before today."
Huenefeld also prescribed him medication for his ulcers, which Deb said should clear up in about a month.
"Pricey, but it will help him put on good weight and, besides, who wants to live with ulcers? Almost all racehorses do.
"After Shaun was adjusted I noticed his hip bones sat more centered, and he was moving well. We have the OK to start working him, and Dr Randy encouraged adding more muscle mass to his hips.
"He's still more muscled on his right side, but I'm hoping with some exercise, we'll be looking at a more symetrical body.
"As you can see [from the pics], he's looking more like a horse that lives a good life! Can't wait to do some hard trotting down our miles and miles of dirt roads with him! Can you imagine? Opening it up and flying on him?"