The obvious answer is that showing us the reality of the hen's life would decrease egg sales. Consumers are misled by idyllic barnyard scenes with hens brooding in nests and chicks cheeping behind their attentive mothers. They also have excellent vision and see a colour range similar to that seen by humans. The severed nerve endings in the beak develop into abnormal nervous tissue, and the beak never heals properly. A hen's nesting desire is so strong that she will go without food and water to be allowed to use a nest when she's ready to lay.
Hens suffer foot and feather damage from poorly designed wire cages unsuited to their needs.
The wire floor does not allow dustbathing, or scratching, or pecking at the ground for food. The cramped quarters do not even permit normal preening. The complete lack of exercise, coupled with the demands of high egg production, cause bone weakness, predisposing the hens to broken bones. Many laying hens are subjected to forced moulting, during which food is typically withheld for up to twelve days. This shock treatment causes almost all the birds to moult rapidly at the same time, instead of at their natural pace.