The Copenhagen Zoo has killed four lions in preparation of the arrival of a new male lion after it failed to find them new homes. The lions, two cubs and their parents, were the same ones that fed on a giraffe they put down last month. NBC news reported the zoo received death threats over the public killing, skinning, and disposal of the giraffe. “The children of the staff of Copenhagen Zoo should all be killed or should get cancer,” one read. The zoo posted photos of the event on their website.

“Because of the pride of lions’ natural structure and behaviour, the zoo has had to euthanise the two old lions and two young lions who were not old enough to fend for themselves,” the zoo said in a statement to the BBC, adding that the male cubs “would have been killed by the new male lion as soon as he got the chance.”

Twitter exploded with outcry over the move:

TELL COPENHAGEN ZOO TO STOP KILLING HEALTHY ANIMALS!! http://t.co/em8ny8hNyS

— Maggie Schafer (@Veggiebabe1) March 26, 2014

If you raise animals in captivity you should have a responsibility to care for them not just until they become 'inconvenient' #CopenhagenZoo

— Melissa (@AtheistMel) March 26, 2014

#CopenhagenZoo People ask what they can do. We've been tackling zoos for 30 years! Why not join http://t.co/GX4wa80hFf Thanks! Will

— Will Travers (@willtravers) March 25, 2014

Mind-numbing. Not content with killing Marius the giraffe, Copenhagen Zoo now kills family of lions… http://t.co/07UPaCCf8x

— The Logical Narwhal (@LogicalNarwhal) March 25, 2014

The major causes of species extinction: 1. Habitat destruction. 2. Irresponsible husbandry. 3. Copenhagen zoo.

— paul bassett davies (@thewritertype) March 25, 2014

Care2 Petition Site has a new petition stating “the ongoing policy of killing healthy animals in their care is not acceptable and that it is time to review and change their breeding policies and procedures, to allow for the accommodation of healthy animals for as long as they require care.” It currently has 558 signatures of 1,000.

Image via ScottishFilmMakers, YouTube