I see one bad thing, eg: You have your tamed wolf and are in need of a bed, you send your wolf after a sheep, the sheep runs after getting hit, what do you know, lava pit ahead, the sheep runs into the lava pit, along with your wolf O__O See what I did thar, wolves will get them selfves killed alot more now.
"Now pigs have feelings..." is exactly right. What do you consider feelings? It's the response to an action, positive or negative. Before pigs seemed numb to everything they did, whether splashing in water or being stabbed they reacted exactly the same.
Now pigs have a SELF-PRESERVATION, and feelings against being killed. This is a step toward intelligence and ethically should be considered as such.
Imagine a little robot toy that screamed every time you punched it or dropped it, would you want to keep doing that and why? Why would you want to cause any being, natural or digital, distress?