Hi. I'm glad you posted about this as I am interested in the same subject. I am a Christian and have been a vegetarian for about 10 years. Partly to lower my environmental impact, but also because I too was horrified to discover what "hog factories" and such were like. I am no theologian but these are my musings:
As far as I understand the Bible, it is not inherently sinful to eat meat or wear leather/fur/etc. After the Flood, God permitted people to eat the meat of clean animals, and as Christians are set free from the Law of Sin and Death, we have freedom through Christ from the laws of clean and unclean animal consumption. While animals are reflections of the awesome creativity and imagination of the Creator, they are not created in His image and so killing them is not a sin (as long as it is done in order to meet our basic needs and not out of cruelty or something). But some people are gifted of God with particular sensitivity to certain things and should listen to their convictions.You know that old passage in Romans about not looking down on those who abstain or those who partake, it's all a matter of what God lays on our hearts...
In modern America, it is almost impossible not to support or patronize some awful industry. People just don't realize when they go to Wal-Mart that it's one of the biggest employers of sweatshops, or that their morning coffee was likely produced by slave labor, or that their chicken dinner came from a chicken with its beak chopped off. Plenty of people who are wholly devoted to the Lord go about their daily business clueless as to what they are complicit in.
I tend to be wary of people who are seeming to use church as a forum for their political views. I feel strongly that church is a place for worshipping God and for the spiritual edification of the body, and for the spreading of the Gospel. Anyway, if I were you, I would not launch into a sermon on the evils of meat consumption, but maybe come at it from an angle of Christian simplicity. Simplicity is such an important part of the pursuit of the deeper Chrisitian life, and it's a message that American Christians sorely need to hear and take to heart. You could talk about the old Catholic tradition of not eating meat on Fridays, and about its value not only for the abstainer, but also the larger environmental/ social implications. This would give you an opportunity to slip in some explanation of modern day meat packing without it seeming like you're attacking something most of the congregants take for granted. In his classic, Celebration of Discipline, Richard J. Foster laid down some guidelines for simplicity. I don't remember all of them but they included, "Reject anything that breeds oppression of others," "Buy things for their usefulness and not for their status," and "Develop a deeper appreciation for God's creation." If you were to study this book and go through all 9 or 10 guidelines for simplicity, when you get to the one about oppression, you could pass around a handout on some of the things we buy that breed oppression of others, and you could include details of the meat industry along with info on slave labor and sweatshops.
Sorry this is so long, it's just my personal opinions, anyway thanks for getting me thinking about it. Good luck & God bless.
OH and thank you so much for the book recommendation, I am totally interested in checking it out!