I don't pull one, but have a good friend who has a one-horse, basic model that she pulls. She has miniature horses, can put 3 minis AND an EE mini cart in there, and it's still not crowded!

   As roomy as they are, with that high ceiling and airy interior, and as long as the available vents are left open(including the upper half of the back 'door' (above the ramp), I shouldn't think it'd be cause for concern. She lives in Albuquerque, and pulls mostly around NM, where it can also be very hot(though it's a DRY heat!! )

  If I didn't need a larger trailer because I sometimes drive a pair(of minis) and haul their vehicle in the trailer also (I use a 14' steel stock combo, very basic)--AND I could afford it, I'd look CLOSELY at a Brenderup--esp. now, with fuel prices as they are and probably will stay....

Margo in NM

(though it's a DRY heat!! )

Whenever people tell me that I always respond with "So's your oven. And it cooks stuff just as well as a pot of boiling water.  (and burns stuff faster!)"