The Results of Artificial Lights in Winter. IV. Die Folgen intensiver Winterbeleuchtung von Zuchthühnern auf die Eierleistung und auf den Ablauf der Brut. Dr. Bartsch. Archiv für Geflügelkunde, 1939, Nos. 10, 11.

Summary:

III. The experiment about the effect of artificial illumination upon breeders having been finished the progeny of the illuminated birds (pen I) and the birds not illuminated (pen II) was in the course of one year tested as to egg production and condition of health while being managed according to usual farming practice. No difference between the two groups could be established. In twelve months the pullets of the first group had an average production of 181·6 eggs, the pullets of the second group 180·0 eggs. The losses were 6·1 per cent. and 9·4 per cent. respectively. 41·9 per cent. of the birds of the first and 41·7 per cent. of the birds of the second group were kept for another laying year. No detrimental effects of the artificial illumination of the mothers could be noticed in their progeny.