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Changes in brown eggshell color as the hen ages
A Z Odabaşi1, R D Miles, M O Balaban
1Food Science and Human Nutrition Department, University of Florida, Gainesville, FL 32611-0370, USA.
Poultry Science
|January 20, 2007
Summary
As hens age, their brown eggshells become lighter due to increasing egg size, not changes in pigment. This study quantifies eggshell color changes and provides sample size recommendations for future research.
Area of Science:
- Poultry Science
- Animal Science
- Colorimetry
Background:
- Eggshell color is an important quality trait for commercial brown eggs.
- Age-related changes in egg production can influence egg characteristics, including shell color.
Purpose of the Study:
- To investigate the effect of hen age on brown eggshell color.
- To quantify the relationship between egg size and eggshell color.
- To determine optimal sample sizes for brown eggshell color studies.
Main Methods:
- Color measurements of eggshells from Hy-Line brown hens using a machine vision system.
- Analysis using a mixed model to assess between- and within-hen variances.
- Statistical correction for egg weight to evaluate color changes over time.
Main Results:
- Eggshells became lighter (increased L* values) as hens aged.
- Decreased redness (a* values) was observed with increasing age.
- Egg weight was a significant factor influencing the observed color changes, with corrected values showing a slower rate of change.
Conclusions:
- Older commercial brown hens lay eggs with lighter shells primarily due to increased egg size.
- The quantity of pigment per unit surface area does not proportionally decrease with age.
- Calculations suggest 11 eggs per 51 hens are needed to estimate brown eggshell color (L*, a*, b*) within 5% of the true mean.
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