The chart below shows the average price of hogs (dollars/hundred weight) recieved to the farms over a time period of 1975 to 2005.
As one can see, that price remains rather flat over these 30 years. However, the farms
input costs to raise those hogs (fuel, labor, energy costs, taxes, feed, etc.) have gone
up substantially.
This fact has lead farms to become larger. Larger units allow more bulk purchasing of products, more efficient use of labor and equipment, and allow for an increase chance of profit.
"Why the need to be so big ?"