FIELD: poultry farming. SUBSTANCE: forming bird flocks on the basis of duration of embryonal stage; performing homogeneous selection of male and female species with short and prolonged embryonal stage during evaluation or forming bird flocks to obtain progeny with genetically various natural resistance with positive factor difference and limits of lysozymic, bactericidal and phagocytic activity, or nonhomogeneous selection of parent pairs by embryonal stage to obtain homogeneous progeny free of substantial differences and having equal limits of lysozymic, bactericidal and phagocytic activity. EFFECT: increased efficiency in obtaining stable and homogeneous bird progeny. 6 tbl
