Categorisation and causes of abnormal egg shells: relationship with stress.

Area of Science:

• Animal Science
• Poultry Science
• Animal Behavior

Background:

• High incidence of abnormal brown egg shells prompted investigation.
• Egg shell abnormalities include misshapen, bulging, and coated (dusted, white banded, chalky, pink) eggs.

Purpose of the Study:

• To investigate the relationship between stress/disturbance and egg shell abnormalities in hens.
• To explore the potential of egg shell quality as a non-invasive stress indicator in poultry.

Main Methods:

• Observing egg production and shell quality after hen translocation (pens to cages).
• Assessing shell abnormalities following flock disturbances (deep litter, nest exclusion).
• Administering varying doses of adrenaline and observing subsequent egg shell quality.

Main Results:

• Translocation and flock disturbances increased abnormal egg proportions.
• Nest exclusion led to egg retention and coated shells.
• Adrenaline administration caused dose-dependent increases in abnormal shells, linked to egg retention duration.
• Specific abnormalities correlated with the timing of disturbance during egg formation and retention period.

Conclusions:

• Stress and disturbances are key factors in abnormal egg shell formation.
• The type of egg shell abnormality can indicate the timing and duration of stress during egg development.
• Egg shell quality assessment may serve as a valuable tool for monitoring stress in laying hens.