We started with about 5,000 head of cattle, and arrived with over 10,000; of course, consuming mostly turkeys, chickens, sheep, hogs, and the cattle of the country. As to our mules and horses, we left Atlanta with about 2,500 wagons, many of which were drawn by mules which had not recovered from the Chattanooga starvation, all of which were replaced, the poor mules shot, and our transportation is now in superb condition. I have no doubt the State of Georgia has lost by our operation, 15,000 first-rate mules. What is the main idea of the excerpt?
The Southern mules were starving.

Sherman’s troops took mules and other animals from Southern civilians.

Sherman thought it was important to leave Atlanta with a lot of wagons.