Optimum Shell Thickness for Best Hatching

Correct Answer: 0.33 mm

The optimum egg-shell thickness for the best hatching result is 0.33 mm. This allows adequate gaseous exchange (O₂ in / CO₂ out / H₂O out) through the shell pores while maintaining structural integrity for the developing embryo.

Shell Thickness and Hatching

• Shell that is too thin (< 0.30 mm): excessive moisture loss, poor structural support → weak chick or embryo death.
• Shell that is too thick (> 0.50 mm): impedes gas exchange and makes pipping (breaking out) difficult for the chick → dead-in-shell.
• Each egg has approximately 7,500–17,000 pores; maximum pores are at the broad end (where the air cell and embryo head form).

Note on Question 101 vs 109

• Q101 — Range for standard quality egg: 0.30–0.50 mm
• Q109 — Optimum for best hatching: 0.33 mm (specific value within that range)

Why Other Options Are Wrong

• 0.22 mm → too thin; gaseous exchange would be excessive, leading to desiccation of the embryo.
• 0.43 mm → within acceptable range but not the optimum for hatching.
• 0.50 mm → at the upper limit; can impede pipping and gas exchange.