Cotton trailers have not been used to haul cotton in years, ever since the invention of cotton module builders. However, they’re still around. They are used for a variety of uses, the most common are rolling, roadside billboards conveying a political message, advertising businesses or supporting political candidates. You can still find them in farm equipment yards used as trash receptacles for used containers. They are even used as animal pens. They once were used in cotton fields as overnight habitats for weeder geese (if you are old enough to remember weeder geese).
Here is a collection of cotton trailers (and one old manure spreader) along Highway 99 north of Fresno, Calif., and Highway 152 from 99 to Los Banos, Calif.