chickens in the south

Does anyone have some recommendations for a dual purpose bird in our hot humid summers here in Georgia? I want to use heritage Birds so that I only have to buy chicks once. Also I am going to turn an old shed into the coop, so what are the basic requirement that a dozen Birds would need for a coop?

My salmon favorelles have had no problems handling the summers and winters here in upstate SC, free ranging and producing eggs all year round. All of my coops are movable so I can move them to new ground every few weeks to keep excess manure and chicken traffic from occurring in any one location.