It would boggle the minds of Congress if they did really constructive surveys on just how many ag jobs are possibly held by illegals in this country. They won’t, of course.
But the upshot here is that the number of illegals employed in ag wouldn’t add up to 1 million.
There are less than 2 million farm owners in the US now. Most farms in the US make very little money (the USDA considers anyone who received $1000 or more in ag production revenue to be a ‘farmer’, so the threshold to enter the stats is really quite low) and employ no one other than the farm owners.
Most of the midwest farms (corn/beans/wheat) are highly mechanized, with machines doing the vast majority of the work.
The majority of the US ag jobs held by illegals or even legit temporary workers are in some vegetable and fruit crops, where harvests are still done with a large manual labor component.
So clearly, the rest of the “12 million” (if we collectively believe the number is that low) aren’t in ag. They’re doing something else.