The objective of the paper was to estimate the amounts of the impurities obtained in the feed production process, depending on the kind of a compound, and to compare the amounts of the received impurities depending on the mixing time. The scope of the paper included conducting research experiments for three compounds varying with the formula with 8, 12 and 14 ingredients for various mixing times: 20, 30, 40, 50 and 60 minutes. The measurements of the mass were carried out in several points of the process line: an impact screen, a cyclone separator, a shaving and dust extractor, and in the final product. The research issue of the paper was to determine whether mixing time along with the additional recirculation of the components influences the quality of the obtained compounds. The following hypothesis was put forward: the longer the mixing time, the fewer impurities in the product, so the better the quality of the compound. In case of the 8-ingredient compound feed the hypothesis can be adopted, but in case of the 12- and 14-ingredient compound feeds, the hypothesis must be rejected.