[bainsfather]

None of our animals' waste is any hazard to you, unless you slip on it!

You are right that it can be done badly, as can many other things. I'd say you are actually arguing against badly regulated animal farming (especially since you mention the US), rather than animal farming per se.

[wiredfool]

Hydrogen sulfide is a common killer of farmers in Ireland.

[biorach]

Maybe 1 a year. And this is only emitted in dangerous quantities when the manure is being stirred prior to being removed from storage. So somewhat tangential to original point.