why did they kill the ostriches

This appears to be about a controversial culling event involving ostriches tied to an avian influenza outbreak in Canada. Based on current reporting, the culled birds were at Universal Ostrich Farms in British Columbia, and the cull was ordered by federal authorities to prevent the spread of avian flu after an outbreak that killed birds on the farm. The cull proceeded after legal avenues were exhausted and the Supreme Court declined to intervene, and it involved professional marksmen carrying out euthanasia of hundreds of birds. The situation drew significant attention and protests from supporters of the farm and public figures who weighed in on the ethics and implications, but authorities maintained the measure was necessary to protect wider poultry populations and public health. If you’d like, I can summarize the sequence of events, the arguments for and against the cull, and the legal/background context in more detail.