You might want to revise the first sentence in your reply, because it suggests that these large corporations might not be guilty of any crimes.

You said: "That usually means they're trying to piece together which, if any, laws were broken by the employer."

Also, as a result, many of the chicken slaughtering plants - which were working children, who should have been in school, at the time of the raids - were forced to shut down as a result of the lack of workers. Almost every company that I worked for required ALL workers to furnish Social Security numbers, which they submitted to comply with several US Federal laws.

Here is a news article confirming the time of ICE raids, on a school-day.

Mississippi ICE raids: A manager speaks out at a plant that lost most its employees.
"Lian said he arrived at work around 8 a.m. Wednesday, shortly after the raid started."
https://www.clarionledger.com/story/news/2019/08/09/mississippi-ice-raids-manager-speaks-out-poultry-plant-ph-foods-morton-lost-workers-detained/1961027001/