I have known this for several years now. But, I remain sickened by it.
Most cows are kept such that they can't walk or even turned around - for most of their lives. That is why you hear of free ranging meat, meaning the cows graze as God meant for cows to do.
Chicken houses are so disgusting as every square inch, even vertically, is being used. Slaughter houses are even worse. Some cows are not completely dead when they are cut up to remove their organs. There are many documentaries on this subject. One doesn't need drones to expose this. Just use a search engine, if you REALLY want to know. It really affected me and it still does.