The Porosity of the Egg-Shell in Relation to Hatchability

Abstract

INTRODUCTION INCLUDED in the group of physical characters which have been studied in relations to their possible influence on the hatching power of the hen’s egg are such factors as egg weight, egg shape, thickness of shell membranes, number and size of shell pores, shell weight, and the linear measurements of the egg. These studies are at best only relative indices of hatchability since heredity, nutrition, and care of eggs before and during incubation all have important rôles in determining and affecting hatchability. Olsson (1934) states that specific gravity is highly correlated with the weight of shell expressed as percentage of total egg weight, and thus is a good measure of percentage of shell. Whereas the specific gravity of the egg is 1.085–1.090 immediately after laying, that of the shell is 2.325. Almquist and Holst (1931) measured shell texture by staining the shells with methylene blue. A close agreement was found . . .