Minor nit: I don't think Hindus are prohibited from eating pork. AFAIK.
> And I would bet that my environmental impact isn't all that high.
Ironically this page claims that lamb is the worst of all meats wrt CO2 footprint.
Also, I've thought about that for lamb, since it's such a small animal compared to pigs and cows. It's partly why it's so expensive. However, I bet a lot of that impact is because very few lambs are raised in the US, and most is imported from New Zealand and Australia. Since I'm in Ontario, Canada, that's less of an issue for me since most of my lamb is raised locally.
In fact, my fiancee's brother-in-law is Greek, and during Orthodox Easter, they go up to a farm, pick a lamb, have it slaughtered, and bring it back to roast on a rotisserie. (If you can ever do this in your life, do it!) So the carbon footprint is probably as low as it's going to be here in Ontario.