An experiment was conducted for investigating the effect of a medicinal herb, fennel, on the production performance, qualitative properties of egg and morphology of the laying hens’ ovary in Qazvin Province, Takestan County, Kahak Village. The subjects of this experiment were 55-week-old white shaver hens. The experiment was carried out within a completely random block design with four different treatments. The experimental treatments included an evidence group (with no use of hormone and extract), a group treated with 2.5mg estrogen hormone, a group injected with 10mg fennel extract and a group treated orally with 10mg fennel extract. The experiment results indicated that the experimental treatments significantly influence the egg production, egg weight, yolk weight, estrogen, calcium, liver weight, abdominal fat and the large white follicles but no significant effect was documented on such traits as triglycerides, cholesterol, large yellow follicles, small white follicles and small yellow follicles.
