STUDY OF THE PHYSICAL PROPERTIES OF THE HEN'S EGGSHELL IN RELATION TO THE FUNCTION OF SHELL-SECRETORY GLANDS

Abstract

1. The data from 3,998 eggs show that the breaking strength and the thickness of eggshell are in the average 4.46 kilograms and 0.311 millimeters.2. There exists a positive relation between the breaking strength and the thickness of an eggshell.3. The breaking strength and the thickness of eggshell vary with individuals.4. The variation of breaking strength and thickness of eggshell is the least at the time of heavy egg production. Therefore, the mean value of either the breaking strength or the thickness of eggshell may be easily determined by a few observations during the cycle of heavy egg production.5. The porosity vary with the breaking strength and thickness of eggshell. The pores of the thick shell are small and numerous, while those of the thin shell are large and few in number.6. The physical properties of eggshell presumably depend upon the individual function of the secretory glands during egg formation more than any other external factors.