I'm in Texas and my barn aisle runs N/S (not perfectly but as close as I could get it while lining up to the driveway). The builder offered to insulate the roof and I think it's the best option money I spent. They do have fans but in 100+ weather the insulation means that they don't stand in their stall sweating.
We are in the most southern part of Maryland as you can get...Our old tobacco bar sits East/West, though we can open doors from the ends and the middle for venilation (pretty neat setup).
When we built our new barn we built the center aisle NW to SE, it sits on the highest point of the property (which isn't really very high) and we get a great breeze going through in the summer. During the winter I usually only have to close one set of the doors in the aisle.
Keeping the barn aisle parallel to the prevailing summer breeze will cool the stalls quite efficiently, as the air movement down the aisle will draw air from the stalls the way a river will draw flow from tributary streams. This may not be a perfect analogy but it is a functional one.
This has NOT been my experience. I have traditional stall fronts- wood below and bars above. Very high ceiling, too. But when the breeze comes down the aisle (on rare days), the stalls are hot.
The OP is in the South where heat, not cold, is the enemy. Even in No. VA temps are quite temperate (compared to, say, Superior, WI). Cold snaps are just that and come and go rather quickly (relatively speaking). In cold climates different standards might be more appropriate.
In the South you want a fairly high ceiling in a barn. Heat rises and the high ceiling gives it a place to go. Ridge vent, turbo-vents, cupolas, or other non-powered ventilation systems allow the heat to escape. Some will also add a large ventilation fan to carry away excess heat. That's OK but increases costs. Careful engineering of "passive systems" will go a long way towards reducing heat buildup without increasing operational costs.
Very true and wise advice. Also be sure to have shade on the south roof and/or sides of the barn. Some barns here hang curtains of textilene fabric to block the sun (these are mostly shed row type TB training barns)
In the South a hayloft above a barn is ill advised. It's great up North where it will provide insulation in the winter. In the South it will just aid in heat buildup. Then, of course, there are the other issues with hay lofts; we'll leave those for another day.