The science that could offer a solution
Tim Doran and Mark Tizard work at the Australian Animal Health Laboratory in Geelong. They were studying poultry disease when, almost accidentally, they made a breakthrough with biotechnology.
Dr Tizard said an embryo could be micro-injected and a green fluorescent protein gene placed on the male chromosome.
"You have a chromosome that tells you whether to be female or male," Dr Tizard said. "We're marking the chromosome that says become male. When you get to breeding to produce the birds that will go on to lay eggs, the mark follows the males and not the females."
Once the egg is marked with a new gene, a chick will hatch, which will be used to generate a breeding flock. When the females from that flock are included in a breeding program for layer hens, their male offspring will easily be identified by a laser by their fluoro mark. The eggs containing males will be removed.
Dr Doran said that could be an ethical and welfare win — and that the eggs would not be wasted. "Our concept is that once you remove the male embryos from the incubation process they can go off and be used for vaccine production, which is obviously a very high-value application that can have huge benefits for the community," he said.
Is this genetic modification?
Dr Tizard said international experts agreed genetic modification was not an issue in this case. "The process we use to mark the males does involve a genetic modification, an introduction of the marking gene, the green fluorescent protein gene," he said. "That gene segregates and if it's male it will carry the gene and if it's female it won't. It's an on-off situation; you can't partly carry the gene."