My wife's horses are chewing up the board fence something awful... she tried painting it with used motor oil, and either got it too thin, or they like the stuff. She says capsicum pepper doesn't bother them either... I know there's a few real knowledgeable horsemen on here - looking for solutions. Thanks.

Horses do that. I've never had mules but I'm told that they're even worse. The cure is to get the horses to quit being horses.

They're bored. Cover in metal or stick a mineral tub in the pen.

I learned along time ago, horses or mules,you keep them in an all steel environment. My barn where they can get to it is covered in chain link mesh. Stalls are lined with warehouse mesh panels. Corrals are pipe panels

It is like trying to stop mules from pawing. Put hobbles on the dang things and save you and the mule frustration.

There use to be a product, I think it was called Crib Halt. It came in clear and dark. Clear didn't do any thing, but the dark stuff stopped them. Of course it was taken off the market because it was too toxic.

Boredom. Maybe put in a TV to watch.

Link to a publication on the subject

cribbing, aka wind sucking, isn't the same as one that just chews down fences/boards.....

Yep. Any wood I have is covered by metal if some sort. Flats have steel roofing, 4X4 posts have Sheetrock corner bead.

Llamas will do it to a limited extent. My barn has manufactured wood panel siding. They've eaten a couple holes right through it.

Yea,too many confuse cribbing with just chewy.

Put a hot wire around the fence. One strand is enough. I know you shouldn’t have to but if they can touch something they’ll find a way to screw it up hurt themselves with it or both.

Horses love OSB. I suspect it’s the glue.

When I was young and stupid, I threw a new wood a pallet into one mule's corral.About one a month.Mule was always careful to not eat the nail part. Now I am old,but still stupid, but I did change to all steel enclosures.

What about drywall steel corners?

I have few dry wall corners on my 4x4's. Mules love them after they get worn a bit from rubbing.

Interesting, Vince.
Since I’ve put up corner bead and steel roofing, I have no more chewing issues. No longer having the mare that did the teaching helps too.

Horse's chewing wood I have always heard was called "cribbing". Have had a few horse's over the years and every one of them did it.

Nope cribbing and just chewing are two different things. As Don ( Huntsman22 ) said cribbing is wind sucking

I too grew up with wood chewing called cribbing. If you check out the old Gunsmoke shows, near all of the hitch rails are chewed.miles

Here's a link to the vet school at UC-Davis about cribbing. It's more than just chewing wood.

CRIBBING

Don is correct (as per usual).

Yup. Cribbing is a whole nuther thing. I wouldn't own one myself, but was around them as a kid.

Well, I've had German Shorthair Pointers gnaw off the coffee table legs.

Wood chewing(NOT the same as cribbing/wind sucking) can be caused from a few things.
If the wood chewing came about this time of year, it's fairly normal due to lack of grazing. They will seek wood to chew, peel bark off of trees and branches. Once the grass comes on it'll resolve.

If the wood chewing has been ongoing, it can be from boredom (as already mentioned) especially if they are in a smaller area with no grazing and no free choice hay.
This also leads into another cause, lack of fiber. If they aren't getting enough fiber from grazing or hay they will chew wood.

Another cause is they could be lacking a vitamin that the wood could be providing. Much like horses that'll eat dirt.

It could also be from mineral deficiency.