"In 2012, there were 3.2 million farmers, ranchers and other agricultural managers and an estimated 757,900 agricultural workers were legally employed in the US. Animal breeders accounted for 11,500 of those workers with the rest categorized as miscellaneous agricultural workers. The median pay was $9.12 per hour or $18,970 per year."
en.m.wikipedia.org
So, let's say we gave all agricultural workers work for $9.12 an hour and we wanted to raise their wage to $15 an hour.
$15 - $9.12 = $5.88
$5.88 an hour times the hours per year comes out to a $12,230.4 increase per worker.
Now times the number of workers in ALL of agriculture, 3,957,900, comes out to $48,406,700,160 per year in higher wage cost.
Now, $48,406,700,160 divided by the U.S. population comes out to $151.79 a year in extra food prices per individual or $607.16 per four person family.
Keep in mind, this was with 3.2 million farmers (not ranch hands), ranchers and mangers factored in. Let's try just workers this time, yeah?
$5.88 × 2,080h × 757,900 workers = 9,269,420,160 a year in food.
Now, divided by the population, the new prices are 29.0668553151 extra per individual now.
So, food would only rise $29.06 dollars a year or $116.36 for a four person family.
Now, are you telling me people couldn't afford $150 with that wage hike?