Originally Posted by Vidaloco
I still think untied is best. If the horse has a fit and tries to jump up over a breast bar (yes I've seen them do this) they could get their legs tangled in a rope. Its kind of a catch 22 tie them slack enough so if they fall they don't break their neck and so they can get their head down to clear debris. But tight enough they don't tangle a leg while standing. I just prefer to not tie them. I've seen plenty of horses hauled in open stock trailers with no ties at all and they travel fine. In an enclosed trailer like yours, I see no reason to tie them at all.
This is one of those controversial topics your going to get opinions on both
I agree with not tieing...the less stuff to get tangled in, the better. We use an open, stock trailer, our mares are fine untied and enjoy the open view and fresh air.
Just something to keep in mind. If you do tie, never get a false sense of security that the lead/trailer tie is unbreakable. I've seen plenty of horses spook before the butt bar/door is closed, pull back, and break them.