Most of Canada’s eggs come from caged hens. These birds are not afforded enough space to spread their wings or express normal behaviour. Lack of exercise means their bones become brittle and often snap. In order to prevent pecking and discourage aggressive behaviour the industry systematically de-beaks hens, a process where a portion of the beak is seared off with a laser, causing extreme pain and stress.
These unnatural conditions produce a variety of physical ailments including respiratory illnesses, loss of feathers, long and deformed claws (from wire cages), bone weakness leading to the loss of use of legs, paralysis, and starvation.
Transportation presents another major issue with battery hens as they are subject to mishandling (several hens are grabbed at a time and thrown into transport cages) which can cause injury and in some cases death. Hens then travel long distances to slaughter, although many die during their trip.
The Canadian Coalition for Farm Animals fact sheet on battery hens provides more information.