Not much, though - I'm English, and we worked out it would cost £20k for the various visas. On top of that, you need to pay an NHS premium, even though you would already be paying for it through the usual national insurance deduction from your salary. It will also take 10 years before they are a citizen.
We decided to stay here (Germany). Less costs and, sadly, better health care.
I want to point out that this is not unique to the U.S. - farming in Europe and the U.K. suffers from the same problem. I suspect that many other countries have the same issue too.
I wonder what the effect of raising wages for farm labourers would be? Surely, it would cause inflation. Does everyone get a pay rise, including the farm labourers, to compensate (inflationary spiral) or will we revert back to norm by excluding them?The truth is - we (yes that includes me!) need to get used to a much simpler lifestyle if we are going to fix this. That will be political suicide though... so here we are with the only compromise that is politically viable.