As of 2013, only California and Michigan have passed legislation that will bring an end to the use of battery cages, gestation crates, and veal crates in their states. Not only is the practice of using cages and crates to limit the movements of farm animals inhumane, but it poses major threats to United States citizens and residents as well.
Under cramped and darkened conditions, diseases such as salmonella are more likely to thrive and spread to other animals via animal feces. For example, air can transport the salmonella particles contained within the diseased animals feces to other animals nearby. Such diseases can remain within the bodies of chickens after they are slaughtered, which may cause serious illness and death among individuals -- especially small children.