Egg shell strengh

Synopsis

The experiment was designed to provide more evidence of the reliability of laboratory tests used to assess shell strength by measuring their relationship to egg breakage in the field. It involved all eggs produced by 23 White Leghorn × Buff Rock pullets that were kept in battery cages for a period of 24 weeks.

Samples of eggs from each hen were subjected to four laboratory measurements, namely resistance to crushing by a hydraulic method, resistance to impact by the falling ball technique, specific gravity by the hydrometer method and shell weight per unit area. Correlations between these assessments of shell strength and the percentage of cracked eggs produced by each hen were highly significant.

All four laboratory tests, therefore, gave a fairly reliable indication of the probability of egg breakage in batteries. It was concluded that from a practical standpoint egg specific gravity was the best method used. In future work the recently developed test of shell deformation under load was considered worthy of comparison with specific gravity as an indicator of shell strength.

Notes

Present address: British Egg Marketing Board Experimental Unit, Edgmond, Newport, Shropshire.