If a full 10% of a workforce that size consists of illegal aliens, then there is no reasonable way to assert that the management doesn't know they are hiring illegals. In that case, it's their own damn responsibility to figure out what to do! Maybe try paying US wages?
Wages determined by who? You and your government?
Companies that size pay wages based on what it takes them to remain competitive. Of course another alternative would be your government mandated "living wage" but then you certainly wouldn't be too happy about the company's response to that........ LOL! And for the record, that facility has been in existence for a long, long time and certainly isn't paying minimum wage. The wages paid are competitive for the geographic area as well as the health ins. and pension benefits.
You sound like the typical "Wal Mart" basher who first whines about the outsourcing overseas of work and then whines about the wages being paid to workers whose company's choose to remain here on soil..........
Try as you might, you can't have it both ways.