When is torture unnecessary? For example, factory farmed chickens have their beaks cut off (and there are nerves in there - they're not like nails or hair). This allows you to keep more in a small space, because even those the stress causes them to start pecking at each other, they can't damage each other too much. And if you can keep more in a small space, they are cheaper, and we can eat more eggs.

Thus, it benefits us in some way, but we would not suffer greatly if we had fewer/somewhat more expensive eggs. Is it then necessary?