Food Inc and tortured animals

We watched the "Food Inc" in class, judging from the reaction, I believe many students there would not eat meat at that day just like me.
The animals in this video are born and designed to be killed and eaten. They are chickens but they are not like chickens in our common sense because they just can take a few steps at one time and have huge breasts. They live in crowded and dirty factories and the most important work is to eat that people can sell them and earn money in a short cycle. Those scenes always remind me the marginal cases I learned in my philosophy class.
The marginal cases raised a question: why animals like pig, cow and chicken have lower status than pets like cats or dogs. Many people consider pets as their family members and treat them at a much higher level than animals in factory. And some animal rights campaigners fight against who tortures pets a lot but not animals in factories. It is the time to do something for animals in factories, they are treated like that not because they do not have intelligence but for the human beings' selfishness.
On the other side,  eating healthy is another key phrase in today's trend. It is absolutely not healthy to eat chickens who are dirty, feed with hormone, infected by other died chicken, or full of fat. The way to change this situation can be designed as a trend: eat organic food and eat healthy.