There are a number of significant animal welfare concerns associated with gestation crates for sows, including tangible physical and psychological consequences. Studies document a decrease in muscle weight, bone density, and bone strength due to movement restriction and lack of exercise. Unable to engage in natural rooting and foraging behavior, crated sows often engage in “stereotypic” bar-biting, an abnormal behavior characterized by repeated mouthing movements on the metal rails of the crate. Crated sows also suffer from health problems associated with confinement including a higher rate of urinary tract infections as compared to uncrated sows. Continuous close confinement is a topic of serious ethical deliberation, and gestation crates have been banned in eight states in the United States, Tasmania, New Zealand, and all 27 members of the European Union.
Humane Society International, "An HSI Report: The Economics of Adopting Alternatives to Gestation Crate Confinement of Sows" (2011). IRF. 5.