This release in general was pretty clear, although I have to think their guidance is understated.
However, following makes no sense to me:
"Hog and pork prices decreased approximately 10 percent in the first quarter of 2010 from the fourth quarter of 2009 primarily because the supply of hogs was higher than the market demand. The imbalance between supply and demand was due to a limited outbreak of foot and mouth disease in south China that affected the hog breeding industry."
The disease should lower supply, if anything, raising prices.
To prevent disease from hitting their herds, probably some herds were processed sooner rather than later so the live stock didn't get diseased. The influx of additional hogs being slaughtered caused a temporary over supply, hence lower prices overall.