I have only ever own straight load stock trailers. When
hauling in the beginning I often left my horses loose if they were traveling
alone. Now I have a bigger stock trailer and I put one in front and one in back
though I could probably put in 3 or 4 if I wanted to. The front horse usually
rides forward to eat hay out of the manger. The back horse usually turns
around, but this is their preference in a straight load trailer too (same horse
in front and back usually)