Capable of living 10-16 years, most egg-laying hens are killed at 18 months old, and meat chicken are killed at 6-8 weeks.

Graphic content deliberately avoided. Please click here to view reality for chickens.
Female chicks go through painful debeaking machines as soon as they are born to minimize the harm they can do to each other in the confinement of egg farms and the psychological toll it takes on them.
Unable to ever produce eggs themselves and a completely different breed to the chickens used for meat, the male chicks of egg-laying hens are considered waste products, as are any females perceived to be deformed or weak. They are sorted onto a separate conveyor belt from the healthy females in their first day of life and sent into an industrial blender called a macerator. All commercial egg farms do this – caged, barn laid, free range, organic. This practice is legal and referred to as humane by the RSPCA. [Dominion]
Broiler chicken (for meat consumption) have been genetically modified to grow at such a fast rate, that it would be equivalent of a 2 month old human baby being 600lbs (Eating Animals). Their bodies have great difficulty handling the extreme physical pressure of over-feeding, antibiotics, crowding, and engineered rapid body growth. This makes skeletal, cardiac and metabolic disorders common. 90% of broiler chickens who make it to the slaughterhouse have a noticeably abnormal gait.
