The applied disinfectants affected the improvement of physicochemical parameters of litter by decreasing its moisture and pH. It was demonstrated that the addition of decontaminating agents to litter resulted in a beneficial decline in the microflora of poultry house air. The total count of mesophilic bacterium was reduced most effectively by means of a disinfectant, whereas the total number of fungi and moulds – by calcium oxide (CaO). But no differences were observed in ammonia concentration in the air of the hen houses examined. In poultry houses in which disinfectants were added to litter, the reported death rate and culling percentage were lower as compared to a control broiler house. Birds reared in a broiler house in which litter was disinfected with CaO achieved the highest European Index of Productivity (EIP).