The Influence of confinement on the Production of white leghorn pullets by F. C. Bobby. Report from the National Institute of Poultry Husbandry Experimental Farm. The Harper Adams Utility Poultry Journal 1929, p. 471.

1. 1. The experiment confirmed the previous experiment of the winter 1925-1926. Under the conditions of this experiment confined White Leghorn pullets showed a decrease in egg production. The important condition associated with this decrease in eggs was a glass fronted house which prevented any direct rays of sunlight reaching the pullets when confined to the house itself.

2. 2. That the apparent reason for the decrease in egg production is a lack of sunlight or the antirachitic vitamin, which results in a condition resembling rickets among the pullets so confined.

3. 3. This condition in adult stock appears only after the birds have been confined for two-three months. It has occurred in both the experiments of 1925-26 and 1927-28.

4. 4. That the use of an open-fronted house, protected in a suitable way against inclement weather, and at night, is one definite method of obtaining improved results with confined birds.

5. 5. That the use of 2 per cent. Cattle Cod Liver Oil supplies the necessary food accessory, the absence of which appears to result in the decrease of egg production described.

6. 6. That the birds under confinement without a sufficient source of Vitamin „D” are likely to lose body weight, as indicated by the results obtained in this experiment.

7. 7. That the egg weight is not influenced by the differences in management practised in this experiment.