Creosote is not legal in NC, and
I'm assuming that's true throughout the US. Carcinogen. They do make
special paints that are equine safe and products such as chew stop. I've
noticed that there is a new feed supplement called Quitt (or something like
that) that is suppose to "cure" this problem.
You might want to consider running
an electric (hot) fence line inside your board fences to protect
them.
