Hey Watch That Tail

I think you're right! It's great they found a way to help each other out! Those flies can really be pesky.

I not a country guy, but the little time I've been there, I've noticed lots of pairs of horses, standing like this, head to tail. I think it's a defensive behavior, where they each share the other's tail for fly swatting benefits. That's my theory, and I'm sticking to it.