That's exactly the point the article makes - we care about dogs and cats, so we believe they "suffer". We don't care about pigs, so we say they don't mind being factory farmed.

I don't see what that has to do with consciousness. Suffering is one thing, consciousness is another.

By definition you can only suffer if you are consciousness.

> Physical pain or suffering, as a matter of fact, happens through conscious minds and involves emotional aspects

https://en.wikipedia.org/wiki/Suffering