I was just at a historical farm and they explained this to me! They said that it can often go badly though, like if there’s a storm that delayed shipments, they can all die, which is super sad
My sister worked for the post office years ago. If her office received live birds, and thought they might die (because the owner couldn't be reached to pick up or whatever), an employee could take them home and care for them.
Wait until you hear what happens to male chicks.
At least maceration is a more-or-less instantaneous death, as opposed to slowly starving in a box.