The term characterized farmers having a red neck caused by sunburn from hours working in the fields. I'm not sure what michael357 is talking about. When I was a kid, it became a term of offensive slang, mainly directed to those who didn't take too kindly to modern ways.
Saw something on history channel one time about this ... about coal miners going up against the owners of the coal mine ... about the deadly encounter .. the coal miners to indentify themselves to one another in this "battle" wore red kerchiefs around their necks ... were referred to then as rednecks and at that time it was an honor to be called a redneck because they were fighting for better working conditions in the coal mines
White boys in the sun cooking up a hog. Sooo-eeee!
it comes from working hard outdoors and getting sunburn on the back of neck - so yes, they actually have red necks