The microbiota of birds of different housing types was studied, namely: cage, outdoor and free-range. The number of bacteria Lactobacillus, Bifidobacterium, Enterococcus, E. coli and lactose-positive, Bacillus in bird faeces was investigated. It has been shown that the composition of the microbiota does not depend on the type of their content but depends on the type of nutrition and on the microbiota that was initially located in a farm or poultry house environment. At the same time, the microbiota of birds can change at a young age, but after puberty, it becomes more stable. The microbiota of free-range birds remained stable while maintaining diet and changed with diet changes depending on the season. It has also been shown that litter and soil are capable of retaining significant numbers of intestinal bacteria. Bacillus can colonize birds’ gut, but it is not a permanent participant in the gut microbiota of birds.