within box 10 and is suitably journalled to the rear and front walls 28 30 as best seen in fig3 a flail assembly carried by shaft 44 comprises the like starter elements 46 at respective ends of shaft 44 and adjacent the respective walls 28 and 30 intermediate elements 46 a plurality of flexible belts 48 are secured at one end to shaft 44 in longitudinal spaced relationship thereon the other ends of belts 48 are provided with a shoe 50 of rubber or the like and the overall lengths of elements 46 and 48 are such that they will revolve within the confines of box 10 as will later be referred to in more detail starter elements 46 comprise a rigid bar 52 attached at its center to shaft 44 and includes rigid but pivotal links 54 at each end no invention is claimed in the flail assembly per se as such form of unloading mechanism is well known on manure spreader devices however it can be noted that where chain elements have been conventionally used in flail devices i have utilized the flexible belts 48 for reasons that will become apparent as this description proceeds a curved baffle or shield 56 as best seen in fig5 and 6 extends longitudinally of the interior of box 10 relative to side 22 the curvature of such shield is in effect a continuation of the curvature of bottom 26.