You just said that animals are tortured and then killed. I pointed out that farmers usually do not want to torture their cattle, on the contrary. But the end goal for the farmer is meat/eggs anyway.
So the Bertrand Russel's question -- is the farmer kind to their turkey?
And there's small portion of animals that happy to do what they are doing (shepherd dogs, sled dogs, even pull horses become sad without work), they are bred this way. Not sure whether we can call that slavery.