Experiments on chickens in 1950s lead to creation of a new breed of animals – broilers. Their main characteristic is fast mass gain and quick growing cycle lasting around five to seven weeks. After this period their mass gain and growth rate are much slower compared to amount of food needed. Broiler’s overgrown muscles are causing big stress on joints, leading to painful deformations. Chicken’s heart is often not able to support its own body mass.
Chickens are held in growout houses with no access to outdoor and often with no windows. There are no stimuli that the birds would get in a natural environment. Stock density can be as high as 33kg per square meter, which means that there are more than 16 2-kg birds per 1 square meter, so one bird has space of one A4 sheet of paper.
Towards the end of the life cycle broilers are captured, packed into plastic boxes, and taken to a slaughterhouse. During catching and transport the animals often sustain even more injuries. The chicken is therefore killed at the moment when nature itself wouldn’t allow it to suffer more. In Poland around 1 billion of broilers are slaughtered yearly.