Hasn't the Obama admin changed the laws on child labor concern ag jobs as well?
When I was a kid under 16, I made some pretty good money (for a preteen-young teen) working for a seed farm detassling corn, a Christmas tree farm trimming trees, and a veal farm building stalls. Yes there were migrant workers in these operations as well, but probably only 1 for every 20 or so kids. A lot of other kids my age did similar work- bailing hay, picking fruits/vegetables, etc.
I'm not even sure that kids 12-15 years old can even legally do these jobs anymore.
The 'cheap' labor we get from open borders is very expensive when you consider the cost of all of the negatives that also cross the border.