A non-invasive technique that uses light to reveal the hidden contents of chicken eggs could allow know the sex of the chicks before their birth and help stop the practice of killing millions of them at birth if they are males.
A study published in Newton magazine and headed by Milan Polytechnic (Roma) indicates that when light penetrates the intact shell of a bird egg, it bounces back and forth, and the photons travel up to two meters inside the tiny four-centimeter interior of the chicken egg.
Optical spectroscopy techniques, which non-invasively reveal the physical, chemical or structural properties of a sample using light, have traditionally been used in medicine or to address agricultural issues, such as measuring fruit and wood.
By illuminating the optical structure of chicken eggs, researchers could determine the sex of the developing embryo inside, assess the quality of the egg’s interior, and determine whether they have been fertilized.
Although these light-based techniques have also been used to study the properties of eggs, “the complex way in which light propagates through the egg is largely ignored,” explained Lennard van den Tweel of incubation technology company HatchTech BV and one of the study’s signatories.
This phenomenon, which had not been observed until now, could help investigate the contents of the egg in a non-invasive way, even during embryonic development in fertilized and incubated eggs, which would allow us to address the ethical dilemma involved in the selective slaughter of male chicks, the researcher added.
Because male chicks cannot lay eggs and do not grow fast enough to be profitable, more than 300 million of them are slaughtered shortly after hatching each year in European incubators alone, the magazine notes.
To investigate the still-unknown optical properties of chicken eggs, the researchers measured the time it takes for light particles, or photons, in the visible and near-infrared wavelengths to travel specific distances as they pass through whole eggs.
The team studied the role of the eggshell as an integrating sphere that traps photons within the enclosed space and analyzed their behavior as light passes through the shells, both before incubation and during the eight days of embryonic development.
The researchers also want to study how the effects of the photons they have observed change throughout the development process of the chicken embryo, as well as the optical properties of each of the components of the egg.
