It is good to see you have mercy for pigs. If all pigs eat grains, instead of grass, how much human food pigs have to consume per year? Today pets, such as dogs and cats consume human food as well. Their owner buy food from stores. The earth has operation constrains to produce as much food as we want. Those animals will drain human food in the world market, drive up prices, and cause famine for poeple in poor countries.

Humans always believe they can be perfect, they are not.