Investigation of the effect of probiotic strains on the productivity of laying hensSergey Tresnitskiy, Anatoliy Tresnitskiy, Andrei Rudenko, Galina Zelenkova, Alexey Zelenkov, Andrey Medvedev and Pavel RudenkoE3S Web Conf., 371 (2023) 01052DOI: https://doi.org/10.1051/e3sconf/202337101052