I was wondering why in the hell Hershel was with the group as well - it made no sense. It should have been Rick, Daryl, T-Dog and Glenn - and they should have tried to lure the zombies out instead... but hey, it's a TV show and even in real life, people do stupid things.
As for Hershel's leg, I'm assuming he'll live... in the books, one guy who does get bit in the jail does die... but also, Dale (who died in Season 2) was bit later, and they cut off his leg, and he lives - so who knows. I'm assuming Hershel hangs on for a while and gets a peg leg... but man that scene was brutal to say the least. I can't recall seeing anything like it on TV in my entire life.. and that chopping scene rivals, if not beats, anything I've seen in a movie. Holy ****.
Overall, this episode was fantastic and one of the absolute best - and I like how it's been several months since Season 2 ended, with Lori about to pop, Carl growing up some, etc. Can't wait for next week. I'm really looking forward to it.