A bale trailer is a trailer that's specifically designed for transporting bales (hay or straw). Most serve to haul either round or square bales. However, there are some bale wagons that are only designed to handle round bales. The most popular bale trailers have a flat bed with some models also having side rails for additional security. There are also models that have removable headboards and adjustable levelling foot. If one is hauling bales often, bale trailers can be a great investment for a farming operation - especially for livestock operations. There are many different types and sizes to choose from new or used.