PETA activists stage a protest against the killing of male chicks.
A German federal court has ruled hen breeders can continue to kill male chicks after they hatch, a practice that results in the death of some 45 million birds per year in the country.

Key points:

• Killing male chicks can continue in Germany until new techniques can identify the birds' sex in the egg
• Male baby birds are killed shortly after birth — usually by grinding or gassing
• Agriculture Minister Julia Kloeckner said that the mass killing of newly hatched chicks is ethically unjustifiable

After their sex is determined, billions of male baby birds worldwide are killed shortly after birth — usually by grinding or gassing, the BBC reported.

The ruling allows male birds to be culled en masse until new procedures to avoid doing so —by identifying the birds' sex inside the egg — are in place.

The Federal Administrative Court ruled in a case involving a hatchery specialised in egg-laying hens that killed male chicks, because they will not lay eggs and the breed is unsuited to raising for meat.

The hatchery was banned from doing so in 2013, but courts in the western state of North Rhine-Westphalia then reversed that ban.

Germany's animal protection law states that no-one is allowed to cause an animal pain, suffering or damage "without reasonable cause".

The federal court said a company's economic interests do not justify killing male chicks.

A crate of new chicks at a chicken hatchery.

However, it said that techniques to determine chicks' sex in the egg should soon be available and hatcheries should not be asked to change their practice twice in a short period of time — first being forced to raise male chicks and then to adapt to the new techniques.

Agriculture Minister Julia Kloeckner said the mass killing of newly hatched chicks is ethically unjustifiable and "this practice must be ended as quickly as possible".

She said her ministry was investing more than 8 million euros ($13 million) to support initiatives to make it unnecessary.

Greenpeace called on Ms Kloeckner to set clear deadlines.

"She must ensure that the animal protection enshrined in the constitution covers all animals in agriculture," the group said in a statement.