Jonathan Safran Foer, author of Eating Animals, talks about factory farming practices and its effect on the planet. The 4 minute video below is just part of a larger hour long discussion which can be found here. It's refreshing to have such a well spoken individual talking about Veganism.
Here's a nerdy video from the 1990's about Veganism. It covers the why, how, what, etc surrounding a meatless and animal product free life. It's got a few clips of difficult images so be aware. But it's worth the 23 minutes.
I recently found this 80 minute documentary from 1998 called 'A Cow At My Table.' The film covers factory farming, animal rights, the history of factory farming and the various ways we view animals and their place in human society. The creator, Jennifer Abbottincludes old footage ranging from educational movies about farming to silent film comedies about food.
The documentary has difficult images of factory farming practices and the animal slaughter process.
Below is a three-part documentary called 'Sentenced to Earth' from the early 1990's. I don't agree with everything Dr. Marvin Goodkind states but the overarching concept is good. He also proposes a few philosophical points which might get you thinking.
The video itself is pretty dorky at parts but does have some difficult imagery so please watch at your own risk.