Abstract The Harderian gland of 110 laying hens was histologically investigated from the time of hatching to the period of 10 months of age. Tissue sections were stained with haematoxylin and eosin, periodic acid-schiff (PAS) and methyl green-pyronin technique. The research shows that lymphoid tissue is colonised by three types of cells: heterophils, lymphocytes and plasma cells. The number of these cells is directly dependent on the bird’s age. During the lifetime of the hens there gradually comes a shift in the dominance of these three cell types. Lymphoid nodules are detected only in 40-day-old chickens, while later in adult birds the Harderian gland is the organ which contains the largest number of mature plasma cells. Some plasma cells contain Russell bodies with different size and shape.

Bosnia and Herzegovina has always had a developed sheep production, at least from the aspect of the number of sheep per capita. Today, the ratio is 1 sheep per 4 persons, because the cattle production, globally looking, is decimated by war. Thanks to the geographic location of the country, the quality of mountain pastures and environment that is still healthy, we believe that with increased investments in sheep production we could increase the number of heads, which would have positive effects on production of meat and milk of exceptional quality. The study involving the uterus of Dubska pramenka during sexual season under nomadic conditions of holding, demonstrated that, in adequate zoo hygiene conditions (holding, feeding, treatment of animal), the sheep showed increased reproductive parameters as well as parameters manifested in meat and milk production. In our studies, microstructure of uterus of Dubska pramenka during sexual season shows extremely positive characteristics for nidation of the egg cell and normal development of the embryo. Epithelium of the uterus is in a form of high-prismatic cells, which points to significant cell activity; perfusion and development of myometrium are visible. The uterine glands are extremely well developed and their histological structure indicates increased secretion and preparation of the uterus for gravidity.