Congenital abnormalities in dead-in-shell chicks associated with mixed bacterial infections

Area of Science:

• Veterinary Microbiology
• Poultry Science
• Embryology

Background:

• Embryonic mortality impacts poultry industry profitability.
• Understanding mortality causes is key to improving hatching outcomes.
• Late-stage embryonic development is critical for post-hatch survival.

Purpose of the Study:

• To investigate the incidence, frequency, and bacterial causes of dead-in-shell chick embryos in Northern Jordan.
• To identify specific bacterial pathogens associated with embryonic abnormalities.

Main Methods:

• Collected 1,000 unhatched eggs from 10 hatcheries in Northern Jordan.
• Assessed fertility and identified dead-in-shell embryos.
• Examined embryos for gross abnormalities and performed bacterial culture and identification.

Main Results:

• 35.7% of eggs were fertile, with 58.8% of fertile eggs resulting in dead-in-shell embryos.
• Over 50% of dead embryos exhibited abnormalities, notably neck hemorrhages and beak defects.
• Key bacterial isolates included Escherichia coli (33.3%), Klebsiella pneumoniae (27.3%), and Staphylococcus aureus (21.2%).
• Escherichia coli showed a significant association with neck and beak abnormalities.

Conclusions:

• Bacterial infections, particularly Escherichia coli, are a major cause of late-stage embryonic mortality and congenital abnormalities in chicks.
• Effective hatchery biosecurity and infection control are essential to mitigate economic losses in the poultry sector.
• Further research into pathogen-specific interventions is warranted to improve chick viability.