Our first stall is a stallion stall with escape door, we quite often use it for hay, have had up to 6 bales plus our folding picnic table, we secure it with bungie cords and haven't had a problem. We once put a tarp down first, then the hay, then wrapped the tarp up and over and secured it. No problems at all. 

Sure, they can stretch out wherever there's room - but what's the difference between the stud wall and the frontmost stall wall? 

Just one less stall.

I don't think most folks load their trailers with this in mind.  Otherwise we'd all need three horse slant load trailers for one horse each.  Or five for two, but then they might step on one anothers' toes...

Thanks everyone - I'll pass it on.

i believe the point farmbabe is trying to make is if there is a stud wall and a frontmost stall wall, then there is no where to spread out. if only a front stall wall at least they can spread out to one side.

and if we had our horses best interest in mind....we would just leave them in the field.  they would rather just eat, crap, and sleep anyway.

If a horse would need to spread his feet that far apart for balance (they are already standing at a slant), the driver is going too fast around corners, braking too hard and accelerating too fast. I don't have a stud wall in any of my stalls and I usually haul with all stalls full. My horses would end up scraping eachother's lower legs all up if they were to spread their feet apart that much. Mine never have. And my full wall is not all scraped up from horses trying to do this. IMO, a stud wall does not inhibit a horse's balance.

I think the OP wanted the stud wall in there anyway because they use the first stall for storage. So there would be no difference in a stud wall or the full wall in front. It would still be a wall on the left side only for the horse.

Let's see... rationale for  the stud wall - intent is to use the frontmost stall for storage.

Good:  Big storage space, akin to a "mid tack" for some folks.

Bad:  Um... the horse was going to be in the frontmost stall, so no difference there...  They were either going to be up against the trailer wall or the lower panel of the divider ("stud wall").

Ugly: Pee all over your "mid tack" stuff because one of the geldings unleashed hot liquid yellow fury...  That's where my tarp comes in.  I try to put a mare up front if possible.

I'm not saying that a horse NEVER has to spread its legs for balance. I'm just saying a stud divider is not going to prevent them from getting their balance. If they have to widen their stance that far that a stud divider would get in the way, yes, it could cause an injury to the next horse. After all, they do have to pick that foot up and set it down.

Something to ponder....What is the reason for a stud divider to be there when you have a horse in there? Is it not to protect the horse(s)?

I am, in fact, referring to an artcile written by a veterarian on trailering safety- the injuries seen most by vets when horses are trailered. But again, personal prefernce plays a big role when we haul our horses. Again- stud walls have pros and cons. there are many ways of securing a load as mentioned in other posts.

I don't think it matters if the horseys are playing Texas Hold 'em in there while we're blissfully driving along...  (though the lack of thumbs would make shuffling a PITA).

If you're using the first one for storage, it's no different than the wall.  If you're concerned about its presence when you have to put a horse up there, take out the stud wall.

That whole argument against storage-necessitated stud walls because of the "wall" thing is silly.