A non-invasive optical spectroscopy technique has been developed at the Politecnico di Milano in an international collaboration to reveal the hidden optical properties of chicken eggs, paving the way for new methods to assess fertilization, monitor embryo development, and evaluate egg quality without cracking the shell.

The study, published in Newton (Cell Press) on June 19, 2026, demonstrates that an eggshell acts as an “integrating sphere,” trapping light within the egg and causing photons to travel distances of up to two meters inside a structure measuring just four centimeters across. This unexpected behavior enables researchers to probe the egg’s internal properties using light alone.

The research was conducted through the infrastructure and funding of I-PHOQS and LaserLab Europe by a team led by Politecnico di Milano and HatchTech B.V., in collaboration with Vrije Universiteit Amsterdam and Wageningen University & Research. The findings build on the successful application of diffuse optical techniques in medicine, agriculture, and environmental monitoring.

Using time-domain diffuse optical spectroscopy, the researchers tracked the migration of visible and near-infrared photons through intact eggs before and during the earliest stages of embryo development. By revealing previously inaccessible optical information, the technique could support the development of non-invasive technologies for early embryo assessment, including determining embryo sex before hatching. Such advances have the potential to reduce the culling of hundreds of millions of male chicks each year in European hatcheries, while improving animal welfare and increasing the efficiency and sustainability of poultry production.

Find more info at the following links

https://www.cell.com/newton/fulltext/S2950-6360(26)00156-8

https://www.polimi.it/il-politecnico/news/dettaglio-news/la-luce-puo-aiutare-a-identificare-il-sesso-dei-pulcini-prima-della-schiusa

https://www.rainews.it/tgr/rubriche/leonardo/video/2026/06/TGR-Leonardo-del-25062026-40790689-a73e-493d-8f7b-b61a0ea496af.html

https://www.eurekalert.org/news-releases/1131902

https://www.corriere.it/animali/26_luglio_04/ecco-come-la-luce-puo-salvare-milioni-di-pulcini-maschi-destinati-alla-morte-14ec5678-5781-430e-8de2-505fa2cacxlk.shtml