The Nature and Probable Cause of Rough Egg Shells Laid by Two Lines of White Leghorns

Abstract

Rough, pebbly-textured eggs were found fifteen times as frequently in one line of White Leghorns as in another even at six and one-half months of age.The rough, pimple-like shell texture was caused by foreign masses attached to the outer wall of the outer shell membrane before onset of shell secretion. It is suggested that in the lines of Leghorns studied, these masses are albumen-like debris produced in the magnum.Injections of oestrogen did not cause hens laying smooth-shelled eggs to lay eggs with rough shells. Hens laying rough-shelled eggs continued to lay rough-shelled eggs after two feedings of a drug antagonistic to oestrogen.That a rough shell texture is not necessarily indicative of shell thinness was demonstrated by means of (1) specific gravity tests, (2) microscopic comparisons of smooth and rough areas of shells and (3) measurements of shell thickness in successive rough-shelled eggs laid by individual hens.