Why not welfare instead of rights?
Because welfare will always allow for animals to be used as a means to an end it can never be adequate for sentient beings. Welfare states that animals can be used so long as pain is minimized. A rights position, on the other hand, says that sentient beings have a right to be free from unnecessary pain and suffering. Sentient life is more than a commodity and welfare try as it might, can never overcome this. Regardless of how well animals are treated, when they are needlessly killed because of anothers desire they become a tool.
