Poor hatch results: separate fertility from incubation losses
A low hatch percentage does not identify the cause. Separate eggs set, development observed, embryo losses, chicks hatched and surviving chicks. Then review the batch history before changing management.
Use clear denominators
Hatch of set is chicks hatched divided by eggs set. Hatch of fertile is chicks hatched divided by eggs assessed fertile. If fertility was estimated from candling, label the second measure as estimated. Early losses can look clear and distort the calculation.
Review the timeline
Check egg source, storage duration, transport, equipment readings, turning, ventilation and any interruptions. Compare similar batches where possible. Do not blame humidity alone without considering other factors.
Investigate recurring patterns
Repeated abnormal chicks, unexplained embryo losses or a marked change in breeder health warrants professional advice. Do not open suspect eggs casually in the kitchen or around live birds; ask about safe diagnostic procedures.
Next step: review several batches using the same definitions. Avoid claiming a guaranteed fertility or hatch result from a small test or from a photograph of the best hatch.
Further reading: Mississippi State University Extension - Hatching Quality Chicks. General education, checked 18 October 2026. This article is not veterinary diagnosis or a treatment prescription.