On a slight tangent, while we are on the supply chain of the discussion... I saw a documentary about a migrating lettuce farm out west in your area, that moves the ENTIRE operation (farm/processing/warehouse) seasonally from south to north and back as the growing seasons change... The plant was amazing and every bit of the product is either processed OR recycled... When they finished cleaning up before moving it was just one HUGE empty building, everything moves to the new location...
In the field the grooming/picking is totally automated, the processing is automated and the scraps/trimmings are processed and go to McDonalds and a few other chains for their sandwiches... It was fascinating to me (I used to work in high speed automation design)...
I don't recall the name of the farm but here is a small sample of the field machinery used, the cost of the lettuce to FF chains had better be small since they are basically getting the scraps/trimmings...
http://sanfrancisco.cbslocal.com/201...robot-farming/