Comment by brnt

Everywhere that is never tested. How do you know for sure you are on good soil, and that no contaminated soil was used under your house and garden, which no doubt were levelled before construction started?

This includes feed. Commercial animal foods literally contains waste, such as plastic, due to waste food recycling not being required to be unpacked.

Sure, you _can_ control these things, but more often than not, people don't. Semi commercial hobbyists don't have the money.