Firefighters have gassed 20,000 chicks after they were left suffocating in a cargo container on the tarmac at an airport in Belgium.
The live animals were due to be flown from Brussels Airport to the Democratic Republic of Congo on Saturday, but the flight was cancelled.
When the exporter refused to take the container back, the animals were gassed on Sunday evening, after being kept in the increasingly overheated box.
'Out of their misery'
Brigitte Borgmans, a spokesperson from the Flemish animal welfare authorities - Dierenwelzijn Vlaanderen - said: "We sent a vet to the scene and he decided to put them out of their misery."
Firefighters from from nearby Zaventem were brought in to do it, after the airport's own team refused. A number of the animals had already died before the gassing.
The incident has raised questions about how and why living animals are treated as cargo, with Independent Flemish politician Hermes Sanctorum, an animal welfare campaigner, criticizing the mass killing, saying: "There's no difference between Amazon parcels and animals."
Flemish nationalist N-VA MP, Jelle Engelbosch, added: "We need to ask why living creatures are exported across the world like economic products."