Omphalitis in Day-Old Chicks (Navel Ill / Yolk Sac Infection)
Hatchery manual covering Escherichia coli, Salmonella, and Enterococcus etiology, unclosed navels, foul yolk sac necrosis, and incubator sanitation.
Scientific Overview
Omphalitis (Navel Ill / Mushy Chick Disease) is an infectious, non-contagious inflammation of the navel and yolk sac in day-old chicks. Triggered by bacterial entry into unclosed or poorly healed navels immediately after hatching, it is a primary cause of early chick mortality during the first 7 days of brooding.
Etiology & Hatchery Pathogenesis
Omphalitis is defined as a bacterial infection of the unhealed umbilical tissue, predominantly caused by opportunists like E. coli, Proteus, Enterococcus, and Pseudomonas.
Infection occurs in setters, hatchers, or chick transport boxes when bacterial contaminants colonize moist, unclosed navels, migrating rapidly to infect the nutrient-rich yolk sac.
Necropsy Lesions & First-Week Mortality Peak
Pathognomonic signs and necropsy findings:
- Mushy, Soft Abdomen: Affected chicks are lethargic with distended, discolored abdomens and wet, scabbed navels.
- Foul Unabsorbed Yolk Sac: Necropsy reveals enlarged yolk sac containing watery, foul-smelling yellow-green exudate or curd-like caseous yolk.
- Mortality Curve: Mortality spikes sharply between Day 3 and Day 5 post-hatch, dropping off by Day 7-10.
Hatchery Sanitation & Humidity Control
Since established yolk sac infection is non-treatable, prevention is critical. Maintain egg sanitation before setting, ensure correct setter/hatcher relative humidity (50-60%) to promote rapid navel closure, and sanitize hatcher baskets between hatches.
Omphalitis in Day-Old Chicks (Navel Ill / Yolk Sac Infection) — Frequently Asked Questions
Related Pathologies & Differential Diagnosis
Differential diagnostic screening: Cross-reference clinical lesions and flock symptoms against these closely associated avian pathologies:
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