I think we live sheltered lives. Those chickens on the shelves in the supermarket. The ones we roast in the oven: 68 days old. Not even 10 weeks.
I don't have a problem with meat eating, I really don't. Lamb, duck, beef, veal, venison, pork, chicken, Turkey... All of it. Fine. I won't eat foie gras, no matter how delicious it supposedly is, despite the fact that I adore liver, because shoving a tube down a goose or a duck's throat and force feeding it is not on my list of acceptable practices to obtain tasty food. I am also choosy about where my meat comes from, because I don't want to pay money for badly treated animals.
I'm also really honest with my children about what they put in their mouths, and always have been. If they ask what's for dinner, I say "Roast pork, that's pig." or "We're having Lamb today - baby sheep". They've always known what it is that we're doing. If they are fussy about eating their meat, I say to them "an animal died so you could have that dinner. Either eat it, or don't eat it, but stop making a fuss about it, because that cow/pig/fish/lamb died so we could eat it." Now that they are getting a bit older (12, 10, 8) I'm starting to talk to DD3, who has never been a 'meaty' person, about whether she thinks she would like to be vegetarian. She looks like she might just opt out largely from meat and enjoy roast dinners!