[Effect o the lighting regimen on breeding chickens of the Plymouth Rock strain].

Studied was the effect of various illumination regimes on breeding birds of the Plymouth line 33. Examined were some hematologic and biochemical indices (vitamin content, erythrocyte count, hemoglobin amount, total protein, calcium and inorganic phosphorus in the blood serum, and alkali reserves of the blood). The liveweight, morbidity rate, development of internal genitalia, egg laying, hatchable eggs and their incubation quality, and the intake of feed per unit of produce were also followed up. Established were the contents of vitamin A, total protein, and alkali reserves of the blood under the effect of light intensity. Besides, some changes in the level of hemoglobin, erythrocytes, calcium, and inorganic phosphorus in the blood serum were noted. Data are given with regard to the changes in the development of the internal genital organs, egg laying capacity, incubation properties, and forage intake per unit of produce as they set in under the influence of illumination intensity.