Here you can see a ball hall. This can be used not only as a ball bearing, but it can also be found many machines. Room for 66 round bales, but you should not hire machines left / right so the space is considerably increased.
It fit exactly 3 balls in a row, thus the beautiful stacked bales from falling over. Should the machinery spaces left / right of the hall for use bales, a storage is not as easy as only the 2 middle compartments are adapted to bale.