The technologies for preparation of compacted feed mixtures involve moistening of feed materials in order to increase the strength of the pellets, as well as to reduce the specific energy consumption of pressing.We investigated the process of mixing with moistening of a model two-component feed mixture consisting of the most common grain and stem components -ground barley and alfalfa hay. The initial hay moisture was 17.5 %, barley initial moisture -11.4 %, average length of hay particles -7.6 mm, barley grinding degree -1.2 mm. The studies were conducted using a multifactorial experiment planning technique. In the course of the investigations the influence on the coefficients of the mixing and moistening heterogeneity of the following factors were determined: mixing time (60-180 s), hay content (20-60 %), set humidity of the feed mixture (20-40 %), moistening time (20-60 s). When conducting the studies, the start time of moistening was the start time of mixing. The experiments were conducted on a vertical laboratory mixer with a spiral type working body. The mixer shaft rotating frequency was one turnover per 1 s. After processing the experimental results, the heterogeneity of mixing (in the range 7.56-48.57) and moisture (in the range 8.61-53.27) were obtained as second-degree polynomial functions. The greatest impact on both mixing and moistening heterogeneity indices of the feed mixture has the factor of the mixing time, the least -the moistening time. With increasing the mixing time, the heterogeneity of mixing and moisture decrease. Increasing the content of hay in the feed mixture, increases both the heterogeneity of mixing and moisture, and the effect of this factor on the quality of the feed mixture decreases with increasing the mixing time.