right, in diets of animals. antibiotics are a similar story. mass scale animal rearing is necessarily industrial and awful, so awful that it spills over to humans eating the flesh and working the factories. for pig farming this aussie documentary is good. pig factories look similar in the US, e.g. california's ban of type of farrowing crates seen here is currently being challenged in court

even ignoring welfare, I wouldn't want to eat one of these fucked up animals w fly-caked sores and prolapses and stuff. nasty

(e: oh I see you are vegan per comment thread. leaving this up for pig eaters)