Having grown up on a farm for a few years of my life, I must say I've seen the animals treated well. They've had room to move around, been fed lots of food, and never been beaten or really mistreated.
I did however have to witness one injustice that really bothered me. The process of "de-horning" cattle. Basically they are locked in place in a pen and a person places this metal device, much like reverse hedge clippers over a horn and it slices it off. The cows really bellow and bawl loudly and blood squirts pretty high in the air. After seeing this happen to one cow, I'd had enough and walked 2 miles back to the house.
Another story which isn't as sad, my uncle had this full grown boar pig that was sick and dying. So he decided to put it out of it's mysery and shoot it. He loads up his 6-shot revolver, lol, and shoots him in the head. 6 shots later, the pig still stands. He only has 3 bullets left, so he uses those up. And the pig is still walking around like normal(or as normal as it was with it's sickness). So my uncle just opened up the gate to the pen and walked away. I agree with him, if you can take 9 shots to the dome, you've earned your freedom. The pig wandered out of the gate, and was never seen again.