ABSTRACT BACKGROUND. The proposed design of the flattening device will ensure an increase in the quality of harvested grass feeds, since the time for drying it is reduced, and the adhesive introduced increases the feed value, in addition, the loss of leaf and small-stemmed parts of plants is reduced by gluing them with stems in the total mass of the roll. AIMS. The complex of technological techniques used for the preparation of a particular feed from plants should ensure the maximum possible preservation of their nutritious, physiologically useful qualities. The purpose of this study is to improve the quality of harvested grass feeds by increasing the feed value and reducing mechanical losses. METHODS. The object of research is a mower with devices for flattening and processing grass with an adhesive-nutrient, a centrifugal-type cutting mechanism, a flattening machine with two ribbed rollers. The main condition for the stable operation of the roller apparatus is to ensure the capture of stems by rollers without unloading and clogging. RESULTS. The principle of operation of the mower differs from the prototype in that the mown grass is flattened not by rolling between two rollers, which is effective with low grass yields and low throughput of the device, but by dragging the plants between adjacent surfaces of the protrusion of one roller and the groove of another roller, and the adhesive is applied by spraying onto the grass not before mowing, and after flattening and forming a loose roll forming device. CONCLUSIONS. The analysis of the work was carried out and the theoretical justification of the parameters of the rollers and their modes during the flattening of grass was carried out. The main parameters of the flattening apparatus must satisfy both the condition of capturing the mown grass and its rolling between the rollers at a certain compression force.