Hay and wheat straw are one of the major items used in livestock feeding throughout the world. Different methods are employed to collect and conserve forages. Almost 90% of dry forage is packaged in most countries and also in Iran mainly cubic packages in different size produced by balers, called hay bales. In order to reduce the space required for storage and traortation cost of hay and straw bales, methods such as pilling and recompression are recommended. Therefore, a recompression machine was designed and fabricated by previous researchers in Iran. The mentioned machine was consisted of feed chamber, compression chamber, stress relaxation channel and hydraulic system which contained two hydraulic cylinders for compressing and opening and closing the valve of stress relaxation channel. The device operation was like this, the inlet door was closed by operator and the hydraulic cylinder was activated manually after inserting hay bales into the feed chamber. When the bale was compressed to desirable level, the cylinder was stopped and the hydraulic cylinder of the inlet valve of the stress relaxation channel was activated to open the valve, when tying was manually completed. Then, to continue movement of plunger to push the compressed bale into the stress relaxation channel, the compression cylinder was reactivated. Thereafter, plunger was stopped and the valve of stress relaxation channel was closed to prevent bale backstroke and the plunger was returned to the original place. Hydraulic power was provided from a John Deer tractor which, due to stationary operation of the device, ought to idle during operation. The device needed at least 4 workers to operate whose tasks were feeding bales to the machine, controlling actuators, tying bales and picking the compressed bales from machine outlet. The existing device has some limitations such as manual feeding, tying and controlling of hydraulic actuators; it also uses hydraulic power of tractor. To increase operation speed and optimization of device, some procedures carried out such as increasing compression rate by redesigning hydraulic circuit and cylinder, feeding hay baled into compressing chamber automatically, mounting an automatic bale tying system on the device and controlling all operations using a control circuit. Taking the costs and available credit in consideration, a circuit with a hydraulic cylinder for compressing, a cylinder for opening the valve of the stress relaxation channel and a hydro-motor for feed conveyor was selected among different hydraulic compressing circuits. A chain conveyor system was designed, which, using a control unit, automatically feeds the device once hay bales are placed on it. An automatic double tying system of a baler machine International model was mounted on the device to tie the recompressed bales again. Finally, a Programmable Logic controller (PLC) was installed on the machine to control all its functions automatically. The operation time of the optimized device for compressing one bale, reduced from 288 to 42 seconds, compared to previous device, and the labor force also decreased by approximately 50 percent by eliminating two workers, whose jobs were, respectively, controlling the system and tying bales. Keywords Hay bale, Compressing speed, Automatic tying system, PLC controller, Feed conveyor