I know that knowing who is raising and slaughtering the animals for meat is no guarantee that what you buy will have been raised and processed in an ethical manner. However, it stands to reason that if you do buy your meat from a primary producer and you discover that he/she is abusing workers or animals you'd do something about it straight away, right?
Of course you would.
The news that "the nation's largest kosher meatpacking plant [was charged] with more than 9,000 misdemeanors alleging child labor law violations" should be seen as a reminder that the best way to ensure that your food is produced in an ethical manner is to be as directly involved in it's production as is possible and practical.
Slaughterhouse charged with using child labor