There are differing opinions about the use of the roof vents in a horse trailer. Here's what I was told about hauling in hot weather: Open all side and rear windows (sliders or, even better if you have them, dropdowns). With all of the windows open there's plenty of air coming IN. If you don't want your horses to bake, you want the roof vents to open towards the back to let the hot air (which rises) OUT. Just what I was told by trailer professionals, and very emphatically I might add! So, not to say that open to the front is necessarily wrong, but that if you see someone hauling with the vents open to the rear they're not necessarily wrong either.
