The hen's egg: Estimation of shell superficial area and egg volume from four shell measurements

Abstract

Synopsis In research on egg shell strength it is often necessary to estimate the shell's superficial area or the egg's volume without recourse to water displacement. Accurate methods are available but they entail making numerous measurements of the shell. Approximate methods that require only three measurements are available but suffer from two disadvantages; they entail measuring the distance from the plane of maximum breadth to a pole, which is difficult to do accurately, and they make no provision for variation in the degree of plumpness (marilynia) of the egg at levels between the plane of maximum breadth and the poles. A simple method is described that is free of these disadvantages. Four measurements are made: the length, L, and maximum breadth, B, of the egg and the distances, X 1 and L − X 2, by which the poles project into an annulus of radius R. Each of these is divided by L to give quotients 1, b, x 1, x 2 and r. A skewness parameter p is estimated by solving the equation and its value is inser...