When searching for worms, it is best to look for native worms. People who bring worms from distant lands can end up introducing a destructive invasive species which can mess up the local ecosystem.

Note, I live in an area in North America which did not have earthworms. People who introduced European earthworms destroyed many local ecosystems and doomed numerous species to extinction.

For that matter, the local composters created a loam which is actually better for agriculture than worm poop.