Physical and mechanical properties of eggshell as affected by chicken breed and flock age

ABSTRACT

1. A study was conducted to evaluate the relationship among physical and mechanical properties of the eggshell, as affected by breed and hen’s age.

2. Data on eggshell quality (external characteristics and derived measurements) were obtained from 322 laying hens, from three breeds (Fayoumi, Dandarawi and Hy-Line Brown) during the laying cycle, starting from 38 wks of age for four experimental periods (38, 46, 54 and 62 wks).

3. Eggs obtained from the Fayoumi breed exhibited the highest shell thickness and breaking force. There was a linear improvement in eggshell quality attributes associated with hen’s age up to 54 wks, thereafter a deterioration was found for all breeds.

4. Generally, eggs laid by native breeds (Fayoumi and Dandarawi) had better mechanical properties compared to those produced by the commercial strain (Hy-Line Brown). In addition, the interaction between breed and hen’s age was not significant for any physical property or mechanical attribute. There was a highly significant (P ≤ 0.01) positive correlation between the breaking force and either eggshell toughness or shell thickness, and regression analyses suggested that eggshell toughness was the best predictor for breaking force, followed by shell thickness.

KEYWORDS:

• Breed
• eggshell
• flock age
• mechanical properties
• physical properties

Acknowledgments

The authors would like to thank the Electron Microscope Unit, Central Laboratory, Faculty of Agriculture and Mini-Industries Development Centre, Faculty of Engineering, Ain Shams University for technical assistance throughout the current study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Faculty of Agriculture, Ain Shams University.