The object is to allow to dispose the lock pin of the ejectlock mechanism of the disk device at the outermost side of the disk tray, and to enhance the packaging effective area of the wiring board to its maximum. The method comprises determining a current load on a secondary side of a transformer by measuring a ratio between a secondary side current conduction time and a primary switching period of the power supply and comparing the current load with a predetermined threshold. The leads are connected to either a totally implanted system or a radio frequency system. Therefore, this invention makes it possible to ensure securities for programs to be provided through the network without losing diversifications of programs. The identification tags may be associated with the poultry themselves or they may be associated with the poultry carriers. The hydraulic motor housing is provided with a shell portion to which the rotation drum is fitted through a rotation bearing and a carrier member carrying both ends of a planetary gear shaft and having an outer diameter less than an inner diameter of the rotation bearing, the carrier member being formed integrally to an outer end surface portion of the hydraulic motor housing.