Step 1: Understanding the Concept:
Eggshell strength is an important quality parameter that determines an egg's resistance to breakage during handling, transport, and packaging.
Specialized instruments are used to measure the physical characteristics of the eggshell.
Step 2: Detailed Explanation:
Eggshell quality can be assessed through both destructive and non-destructive methods.
A spherometer is traditionally used to measure the radius of curvature of a spherical surface.
In poultry science, a modified spherometer is used as a non-destructive tool to measure the minute deformation or curvature of the eggshell under a specific, light load.
This measurement provides a direct index of eggshell strength and elasticity without breaking the egg.
A Vernier caliper and a screw gauge are primarily used to measure the physical thickness of the shell after it has been broken and washed, rather than its overall structural strength.
A Haugh meter is used to measure the height of the thick albumen (white) to determine internal egg quality, and is unrelated to the shell.
Step 3: Final Answer:
The instrument used to measure the curvature and structural strength of an eggshell is the spherometer.