I have to say, unfortunately, that I agree with what most other people have said. I read the post and I really couldn't see what was so terrible about it. You got accommodation, food, money and a realistic experience of lambing? I've never been paid or been offered accommodation for any work experience. He was actually being generous by giving all those things, especially when you had no experience of lambing. Yeah, the farmer was rude, but some people are, and experiences like that are character building. I don't agree with the fact he called you names, that's just harsh, but it's a small price to pay for work experience that is basically essential to get into vet school. I obviously appreciate that it wasn't a pleasant experience, but unfortunately, that's the way things are. Just think of it as good practice for dealing with horrible clients in the future!
I've been lucky; I've never had a bad work experience, except at a stables I worked at. Everyone was extremely rude (all except one person there refused to speak to me for the first 2 days, except to tell me what to do) and openly looked down on me because I didn't own my own horse. But, I got through the week and got a half-decent reference out of it.