I saw a horse trailer on the road the other day. The horse had it's head stuck out of a window. It so reminded me of a dog hanging it's head out. I've heard it isn't good for a dog or a person to have their head out the window while traveling. Dirt, dust and other debris get into the eyes and can cause problems. Wouldn't this be true for a horse as well?

Its true that while hanging your head out of a window you can incur injuries from debris and bugs. But have you ever tried arguing with your dog about that? I know mine isn't happy til he's stuck his head out for a couple miles. Some horses are the same way. They might like seeing where they are going or feeling the breeze. I can't say I normally see horses going great distances with the windows open, but on shorter trips its pretty common especially if its hot outside.

Yes, I have argued with my dog before, but I never won. Could you imagine trying to argue with a horse? :D