Fiction, horse escapes barn fire

I read this book about 15 years ago so I’m guessing it’s an early 2000-90’s book but it was also in my middle school library so it could be older.
It’s about a horse that escapes from a barn fire and runs. After running a while he is spotted by a boy who keeps him, after watching the horse run around in a pen the boy realizes the horse loves to jump and he’s good at it because the horse is continually jumping in and out of the pen by himself. So the boy trains the horse up and enters him in a competition I believe they win. That is all I remember about the story
The book itself was a square book, bigger than a normal book it was also red and had a pencil sketch of a horse running down a hill from fire on the cover but it didn’t take up the whole cover just a smaller square in the middle of the cover.

The Horse of Hurricane Hill? Way older book, though -- first published in 1956 and as far as I know only reprinted in the 60s.

Here's a cover image:
https://images-na.ssl-images-amazon.com/images/I/511f96ailEL._SX258_BO1,204,203,...

Here's a summary:
https://www.kirkusreviews.com/book-reviews/c-w-anderson-4/the-horse-of-hurricane...

Oh my god that’s it! I am so excited right now thank you. I can’t believe it Ive searched for 15 years and in less than an hour on here and I have it. Thank you again.

Ha, glad that was the one. I'm a big fan of Anderson's works, so this one was a welcome trip down memory lane.

Yeah, I was going to suggest The Horse of Hurricane Hill as well. Love CW Anderson books and his artwork.