of a small portion of the rubber cylinder having minimal mass and inertia furthermore the elastic reaction opposing this local deformation of the rubber roller wall is also reduced resulting from the small pressure increase produced inside the roller by the local deformation it follows that both the elastic reaction and the inertial reaction in the presence of a foreign object appearing in the nip between the rollers are much less with the inventive conditioner than with prior conditioners and just as reduced are the stresses on the drive members this arrangement not only allows a simplification of the problem of transmitting the motion to the movable support roller of conventional design but also permits the elimination of couplings or safety pins from the drive elements or at least a marked decrease in the servicing intervals and downtime for their replacement a second important consequence of the operating mode of this invention is the following the thickness of the fodder layer 60 being processed is unavoidably non uniform and tends to be higher at the middle of the roller and lower at the edges as shown in fig2 with the conventional conditioner fig1 this greater thickness of the material at the middle reflects itself in the roller such as the roller 2 in fig1 being bodily raised in its movable supports consequently the material at the edges is not conditioned while that at the middle undergoes a more powerful squeezing action than desired with the inventive conditioner on the contrary separation of the rubber roller from the steel roller 10 adjusts itself to the material thickness at all points and the squeezing pressure remains the same all along the roller generatrix this same automatic adjustment of the gap between the rollers will occur each time that the flow rate of.