At different stages of feed production and storage, it is possible to contaminate both feed and their components with various pathogenic and opportunistic microorganisms that can cause infectious diseases not only among animals but also have epidemiological significance. The aim of the study was to isolate biofilm-forming strains of microorganisms from feed, as well as to study the inhibitory activity of the probiotic complex of bacteria of the genus Bacillus against microbial biofilms. Identification and species affiliation of isolated bacterial field isolates were performed by cultural-morphological and biochemical properties. The formation of biofilms was studied by determining the ability of isolates of microbial associations and individual species of microorganisms to adhere to the surface of a 96-well polystyrene tablet according to the method of O'Toole & Kolter, 1998. Determination of microbial contamination of 50 industrial batches of feed from 4 pig farms in two regions of Ukraine (barley, compound feed SK-31 for rearing, SK-51 for fattening pigs, EXCELL starter for pigs 15%, shop prestarter, compound feed for lactating sows). In 11 experimental batches of barley (68.8%) and 13 batches of 3 types of feed (SK-31, SK-51, feed for lactating sows) identified associations with different microorganisms Pasteurella multocida, Corynebacterium striatum, Bacillus subtilis, Leptothrix ochracea, Haemophilus parasuis and yeast Candida albicans. The association of Actinobacillus pleuropneumonia bacteria with B. subtilis was identified in 2 batches (50%) of the shop prestarter. Moderate, by optical density, biofilm formation for associations of microorganisms P. multocida + C. striatum + C. albicans (D620=3.59) and P. multocida + L. ochracea + C. albicans (D620=3.62). Planktonic forms of C. striatum and P. multocida showed low film-forming activity at the level (D620<1.51). Inhibitory activity of the probiotic complex of bacteria of the genus Bacillus (B. subtilis, B. licheniformis, B. amyloliquefaciens) was determined by isolated variations of microbial biofilms in 5 feed species, which displaced all biofilm-forming microorganisms except H. parasuis