Physical trauma

Battery cages cause a wide array of debilitating physical conditions for chickens. The wire mesh floors of battery cages can cause a host of foot disorders, including toe pad hyperkeratosis, which develops due to pressure on certain areas of the feet thanks to the sloping floors of cages. This condition can lead to painful open lesions on their feet. Overgrown claws are also common, since chickens cannot engage in ground-scratching behaviors that keep nails short naturally.

 

Due to genetic engineering and selective breeding, the bodies of hens are compelled to produce unnaturally high volumes of eggs as compared with populations in the wild, or those living in extensive agricultural conditions. This frequency leeches high levels of calcium from the skeletal system in order to produce eggshells, leading to bone fragility. In extreme cases, a syndrome called cage layer fatigue may develop, whereby birds can become paralyzed by calcium depletion combined with spinal collapse from their inability to properly stretch, walk, or stand up. Unable to reach water spouts, they slowly die from thirst.