Free range chickens VS Poultry Farm Cages

As with chickens, they are especially suitable for large-scale production. Their size, egg production and feed conversion ratio (how efficiently they convert food into muscle mass or eggs) are genetic traits that can be easily changed, and the chickens can survive in cages stuffed into barns. As far back as the 20's, chickens were being raised more selectively to maximize their productivity for either meat or egg production, but not both. Their breed diversity and welfare were sacrificed on the altar of productivity, setting the stage for the expansion of the first chicken factory farms and the subsequent application of the factory farming model to pig production. The process, which environmental health scholar Ellen Silbergeld calls the "chickenization" of American agriculture, has given Americans plentiful and extremely cheap chicken and eggs.