There's a fairly comprehensive convention calendar here, although I don't think its search is as granular as by zip code:

http://www.other-worlds-cafe.com/resources/con_calendar.php

The pamphlet isn't advocating against mistreatment out of concern for the animals' welfare; bruised meat is damaged meat, and has to be sold cheaper.

Another mirror:
http://www.webmoose.com/misc/NISOptions.pdf

When I worked at Disneyland several years ago, it was fairly routine for a group of Cast Members to club together and have shirts like this printed at the end of the busy summer season. (Disney didn't officially sanction it, but they didn't forbid it either.) It was sort of a badge of honor to own one of the shirts; it looks like this CafePress user is just ripping those off. I definitely remember a couple of these slogans floating around on Cast Member T-shirts in the early 90s.

Obscurica got it in one. Yay, Hokusai.

Here's the original.