The hen's egg: Shell breakage when two eggs collide

Abstract

1. A theory of egg shell fracture (Br. Poult. Sci., 17: 199–214, 1976) is modified to incorporate the subsequent finding that the energy required for egg shell fracture is dependent on shell compression speed at speeds such as may occur during egg‐to‐egg impact in poultry houses and packing stations.

2. The modified theory was tested by new experimental data.

3. A method which is described enables a designer of cages and egg‐handling equipment to predict the incidence of shell fracture during egg‐to‐egg equatorial impact at any relative velocity, given information about the distribution of the variate X in the population of eggs in question, where

in which R_a, T and e are, respectively, the reciprocal of the average shell curvature, the shell thickness and the thickness of the weak inner shell layer, all measured at the equator, M is egg weight and e is a constant length (about 13 μm).