Did you know Costco sells barn kits? Order a pre-engineered traditional wood barn kit and get it shipped to your building site. You can add an optional horse stall package too! OKAY THIS IS THE BARN I WANT!
In this adaptation from Horse Housing: How to Plan, Build and Remodel Barns and Sheds (Trafalgar Square Books), Richard Klimesh and Cherry Hill describe the basics of better barn building, including layouts and roof shapes.