In this thesis, a tractor attachment - a rotating hay collector that enables rotation of hay, has been designed and structurally elaborated. The purpose of a rotating hay collector, as its name suggests, is collection of hay. The first part of the thesis contains the analysis of the attachment's function, and the latter part contains an overview of existing devices on the market. Based on personal ideas and existing solutions, a functional structure has been developed. For each function there are several partial solutions in the morphological matrix. Following a comparison of concepts, the best one is selected and further elaborated, the required calculations are carried out and a 3D model is created in the SolidWorks software along with technical documentation.