Both, really. Ideally, the animal would be having a happy life until it suddenly wasn't, and didn't exist anymore. Practically, that can mean that they're kept

Both, really. Ideally, the animal would be having a happy life until it suddenly wasn't, and didn't exist anymore. Practically, that can mean that they're kept in their normal surroundings until the last moment, and then they're killed as quickly and painlessly as possible. For example, the farm around the corner has a mobile slaughterhouse come to their pasture. The cows to be killed are put in one pasture, separate from the others. They're killed with a gunshot to the head, then taken away. There's no chance for the cows to stress in transport and know that the day is any different from any other, until the very last second. I'd call that humane.