If the hay is real stemmy like johnson grass, big bluestem etc, even with the rear spacing set to make a 6 foot windrow you will still get balling. Even worse is stuff that has much branchy weeds like queen anns lace, chicory, etc. Even just using one side it will ball up on the wheels and leave giant gobs. Worse is that it doesn't rake clean when it starts to load up. I raked a field for the neighbor last night and will finish it this morning, it's all like that. I spend nearly as much time backing up to clear a plug/ball as I do going forward.