of the wrapper frame 31 extending from the bridge 37 of the wrapper frame 31 is a vertical pole 38 the upper end of the pole 38 terminates with a horizontal boom 39 fixed to the pole 38 and extending over the wrapper frame 31 at a mid point of the foot print of the wrapper frame 31 mounted on the boom 39 is a motor 40 having a belt or chain drive adapted to drive vertical axle 41 alternatively the bale wrapper 30 may be mounted so that the boom 39 extends from the front of the trailer on the underside of the boom 39 and rotatably attached to the axle 41 is an inverted l shaped arm 42 having a vertical arm 43 adapted to orbit a hay bale to be wrapped by the bale wrapper 30 mounted at the base of the vertical pole 38 is a film roll holder 44 in use the trailer 1 is driven alongside a hay bale to be wrapped resting on the ground hay bales should be wrapped shortly after formation for example in warmer climates it is desirable to wrap hay bales within two hours of formation whereas in colder climates a longer delay is not critical provided the bales remain dry the bale.