Candling series, part one: the first useful check
Candling uses light to inspect development without opening an egg. A first routine check around day seven can be informative for chicken eggs, but shell colour, equipment and exact timing affect what you see.
Prepare a quick check
Use a suitable candler in a darkened area, with clean dry hands and a stable place to handle eggs. Keep time outside the incubator brief and avoid unnecessary repeated checks. Do not shake eggs to look for movement.
Record what you can actually see
Use categories such as development seen, clear/uncertain and suspected early loss. A clear-looking egg may be infertile or may have lost an embryo very early. Dark shells and poor viewing can make interpretation difficult.
Avoid premature decisions
If uncertain, follow an appropriate recheck plan instead of immediately discarding the egg as infertile. Leaking, foul or otherwise unsafe eggs require careful management; ask an experienced hatch adviser if you are unsure how to proceed.
Next step: photograph only when it can be done safely and label images with the actual incubation day. Use the fertility sheet to record uncertainty honestly.
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.