A German zoo has killed a dozen healthy Guinea baboons and fed them to predators. Nuremberg Zoo claimed that it had to kill the captive monkeys as a last resort to address an “increase in conflict” caused by overcrowding.

A zoo in the German city of Nuremberg said it killed 12 baboons on Tuesday despite protests, capping a saga rooted in concerns that the zoo had too little space to house a growing group of the animals.

Zoo director Dag Encke defended the decision to cull the baboons in a news conference, saying that the decision had been a “yearslong consideration” and that by doing so, they helped to maintain a healthy baboon population at the zoo, in line with the the European Association of Zoos and Aquaria (EAZA)’s policies.