One-quarter doesn't sound like much to me as a sheep farmer. Our herds double-to-triple every year, and then get cut way back again as we turn the lambs into meat. Pigs have even more offspring: 5-6 piglets per litter, 1.5 litters per year, and can have their first litter at 8 months. "One-quarter of the pigs" should be replacable in less than a year, a minor temporary supply shortage for the meat market.

EDIT: I don't disupte any of the facts of the article, and my use of the world "minor" is from the presumption that people might infer that this is a long-term problem, rather than an acute and quickly rectifiable one which seems "minor" in comparison to a long-term one.