New Zealand egg producers urged to adopt tech to end killing of 4 million male chicks each year

Warning: This report contains footage some viewers may find distressing.

There are calls for New Zealand to put an end to the killing of day-old male chicks in the egg industry.

Germany is outlawing the practice, and introducing technology that'll identify an embryo's sex before it hatches.

Animal rights groups are calling for the technology to be introduced here immediately.

Forget the age-old question 'what came first, the chicken or the egg?'

The question you might never have pondered is what happens to all the male chickens that hatch.

And the answer is confronting: almost all are killed a day after hatching.

"I think it's something the public isn't really aware of," said Save Animals From Exploitation (SAFE) campaigns manager Jessica Chambers.

"We don't normally think of what happens behind the scenes, but this is unfortunately the reality of egg farming."

Last year New Zealanders ate an average of 246 eggs per person.

In the egg industry, males are considered waste. Unable to lay eggs and unsuitable for meat, 4 million are killed in New Zealand every year - either gassed or thrown into a macerator.

“That's where chicks are minced or shredded alive,” explains Chambers.

"It's a situation people don't like to talk about, but it is done under strict welfare conditions," New Zealand Egg Producers Federation executive director Michael Brooks said.

The practice is approved by New Zealand's welfare codes and the SPCA, but technology has now made it avoidable.

Germany has just announced it'll be the first country to outlaw the practice, from next year. Instead, it'll use in-ovo technology to determine the embryos' sex inside the egg early in incubation.

The eggs containing males can then be disposed of before they're born, and used for things like pet food.

SAFE says we should follow suit.

"We would definitely be risking our reputation if we don't adopt this. New Zealand prides itself on its animal welfare standards, and this is a great opportunity to spare millions of animals from pretty horrific deaths," Chambers said.

The NZ Egg Producers Federation says hatcheries here are interested, but it would cost almost six times more to produce each egg, and the technology would need to be tested in a more realistic commercial setting first.

"Everybody wants to look at improvements, and if this is clearly an improvement we'll adopt it when it works,” says Brooks.

And until Germany proves it works, we're unlikely to see change here.