If you still need a reason to switch to organic or no-chemical chickens, I recommend you read the April 5, 2012 New York Times article by Nicholas Kristof. He sites two new studies, one from John Hopkins University and the other from the Arizona State University, that found evidence indicating that factory poultry are routinely fed caffeine, banned antibiotics, the active ingredients of Benadryl and Tylenol and even arsenic. These chemicals and many others were detected by researchers who tested feather meal from factory raised chickens. Although these chemicals were found in low levels, there is some fear that, since arsenic is a drug that tends to build up in the body over time, their presence in factory chickens may pose a health hazard
As comments at the end of the article point out, it is not only through their meat that chemicals fed to chickens can enter the human food chain. The bi-products of factory chickens are routinely returned used in other areas of industrial farming. Feather and bone meals are used in livestock and fish feed. Chicken droppings are spread on fields as fertilizer and often end up in groundwater and rivers via run off. It is easy to see how these chemicals can end up in our food and water.
Perhaps more horrifying than the impact on the food chain are the reasons why farm chickens are fed these chemicals.
Caffeine? So that the chickens will not sleep but instead stay awake to eat and thereby grow faster.
Benadryl? To calm down chickens stressed out by factory farm conditions (and maybe by all the caffeine).
Antibiotics? Well consider the living conditions for chickens on a factory farm.
Arsenic? To make chicken meat, which would otherwise be grey due to poor quality food, look pink.
Anyone for a chicken nugget?
This reminds me of that famous photo of the pink goop (mechanically separated and chemically treated meat) > http://www.huffingtonpost.com/2010/10/04/mechanically-separated-meat-chicken-mcnugget-photo_n_749893.html