Sounds a similar principle to the barbaric and out dated practise of blistering soft tissue injuries. I doubt that it would be effective, most foals straighten on their own which would give believers claim to believe what they'd done was the cause when all it woulds do is cause a superficial tissue injury on the foal. There are plenty of experienced repro vets and farriers, particularly in the TB's these days. I'd suggest you call upon their services. The modern world means you can do so through technology no days if you are in an isolated area.

Do you have your mares on hilly ground by chance?