The inventions relate to agriculture, in particular to fodder production. A method of feed preparing includes mixing whole grain with water or solution of nutrients, grain shredding, and agitation. According to the invention whole grains are fed to a shredder by portions and simultaneously mixed with water or solution of nutrients, the material from the output of the shredder is sent to its input through a cavity of processing container. Shredding process is carried out without air access under pressure of 4 to 5 bar, heating is controlled not to exceed , and the obtained mixture is repeatedly passed through the shredder to achieve value pH from 5 to 5.5 and unloaded. The feed-preparing unit comprises a frame, a drive, a grain hopper, a processing container, a disk shredder, which comprises a rotor with blades and fixed working grindstones mounted to form a gap, and pipes and check valves. According to the invention the rotor of the centrifugal disk shredder has blades in the form of an arc, which are uniformly located along an outer contour of an annular double-sided end crown, on working plane of which depressions are made and additional blades and sharp-angled teeth, which are located between a hub and the annular double-sided end crown, millstones have circular crowns with grooves and corresponding sharp-angled teeth. The input and output of the shredder are connected through the cavity of processing container and the unit is adapted to grind without air access. The invention provides fast and efficient shredding whole grains and other solid nutrients with simultaneous biological processing, fermentation.Винаходи належать до сільського господарства, зокрема до кормовиробництва. Спосіб приготування корму передбачає змішування цілого зерна з водою або розчином поживних речовин, подрібнення зерна, перемішування. Згідно з винаходом, ціле зерно подають у подрібнювач порціями і одночасно змішують з водою або розчином поживних речовин, матеріал з виходу подрібнювача на
