Research Note Effect of Oral Administration of Bismuth Compounds on Campylobacter Colonization in Broilers

A roller device for compacting the ground comprising a rotatably driven first roller facing, whose speed can be modified, at least within a certain range. Device includes a unit for determining the vertical distance between a surface of a compacted ground lying behind the first roller facing and a lowest point of the first roller facing, and by a speed regulating device for modifying the speed of the first roller facing, based on said distance. The speed regulation device allows the speed of the roller facing to be adjusted in such a away that slip is prevented without determining the actual slip between the roller facing and the ground.