Research Note: A Study Relating to the Validity of the Haugh Unit Correction for Egg Weight in Fresh Eggs

Egg weights, weights of the major egg components, and albumen heights were measured on eggs from young and old flocks of the same strain of commercial layer. This allowed investigation of the relationships between these measures and Haugh unit scores (HU). The HU calculation uses a formula designed to correct the height of the albumen to a constant 56.7-g egg. Results showed that the effect of egg weight on albumen height was of minor importance within flocks and inconsistent between flocks. The statistical relationship between albumen weight and albumen height was equally weak. When all eggs were included in one data set, both egg weight and albumen weight significantly affected HU, showing that the correction for egg weight was not adequate. Variation in the albumen height was associated with 93 to 95% of the variation seen in HU. These data suggest that calculation of HU is not necessary for eggs coming from one flock, and is wrong when eggs come from different flocks. Measuring the height of the albumen is suggested as a simple replacement for the HU calculation.