Would these diseases occur if it weren't for mass farming of animals?

I'm the first to admit that I don't have a clue as to how these things work, and as a vegan I am abit biased to this consideration but from what I have read/heard, alot of diseases appear to be a product of the way we raise animals in close proximity to eachother, under unhygenic, inhumane conditions which are entirely unnatural. There have always been 'epidemics' that have hit the UK, from Mad Cow's Disease to Foot and Mouth and more. So, removing any personal feeling we may have on the meat/vegan debate, I was wondering if these problems would arrise under natural conditions? Now, I'm not saying that everyone in the world should be vegan (despite how much I would love that) but it would be difficult for anyone to say that it is right to keep some of these animals in the conditions that they are currently in and state that it is natural. So, if the animals were raised like in the old days where it wasn't considered mass farming (ie. if they were to have room to move around freely as opposed to battery hens). If these diseases were entirely natural, then do you think that they would have spread and become so dangerous if they were raised better (when, for example, it was determined that Foot and Mouthwas probably caused by infected pigs which had been fed garbage that had not been properly heat-sterilized. It is further believed that the garbage contained remains of infected meat which had been illegally imported to Britain. [19])?

Now, I know this subject can be abit touchy for some people as the whole debate seems to bring out the 'angries' in people so I am asking for serious answers that aren't being made into a meat eater/vegan argument. It is something that I've been wondering so would like some informed replies. If I receive any aggresive answers then I will simply leave this thread.

Thank you for anyone who can respond sensibly.

(Edit the question!]

[edit on 18-7-2009 by JennyJen]

Probably not and I wish everyone would be vegetarians too. It looks like we've brought this on ourselves. Thanks for the post.

This is why they are labled beast of burden. Theres a good reason these animals that carry the weight of our whole population should be avioded.