It's very hard to find humanely slaughtered meat. To quote Foer, who in turn was citing a review of some audits of slaughterhouses (emphasis in the original):
>[Grandin's report found] deliberate acts of cruelty occuring on a regular basis at 32 percent of the plants [slaughterhouses] she surveyed during announced visits in the United States. It's such a shocking statistic I had to read it three times. Deliberate acts, occurring on a regular basis, witnessed by an auditor - witnessed during announced audits that gave the slaughterhouse time to clean up the worst problems. What about cruelties that weren't witnessed? And what about accidents, which must have been far more common?
>[Grandin's report found] deliberate acts of cruelty occuring on a regular basis at 32 percent of the plants [slaughterhouses] she surveyed during announced visits in the United States. It's such a shocking statistic I had to read it three times. Deliberate acts, occurring on a regular basis, witnessed by an auditor - witnessed during announced audits that gave the slaughterhouse time to clean up the worst problems. What about cruelties that weren't witnessed? And what about accidents, which must have been far more common?