this experiment was conducted to evaluate the effects of using of zizaphora (thymyus valgaris), peppermint (lamiaceae menthapiperita), menta pulagum (oreganum valgare) medicinal plants on performance, egg quality, blood and immunity parameters of laying hens. this experiment was conducted in a completely randomized design with 288 of hy line (w-36) laying hens in 8 treatments and 3 replicates (...