Some Buddhists -- especially ordained monks and nuns -- don't kill to eat, and don't even participate in farming or other industries.
They have rules of behaviour -- e.g. not digging earth, except if it's clean builder's sand, and drinking carefully-filtered water -- to avoid accidentally killing.
They eat what's given to them (i.e. donated in charity) -- including meat, like beggars, with another rule that they don't accept meat that killed especially for them.
You perhaps might think of "scavengers" on your Worldbuilding question -- eating what's already dead. I've read that monks won't eat fruit unless a lay-person first ritually damages the fruit (to make it "allowable").
The diet of non-ordained (lay) Buddhists varies, some eat meat but wouldn't want to be people who kill animals, some are vegetarian. There are stories from old Tibet of people trying to dig (the foundations of new building) carefully to avoid hurting worms.
The principle scruple seems to be against intentionally killing. There may be some doctrine which says that some accidental killing is inevitable, and is an example of the fact that the world is a kind of imperfect place, which is a motive for pursing enlightenment instead of re-becoming.