A charity says many will spend their lives "suffering discomfort and pain"
Several major food outlets have been criticised in a new report on chicken welfare.
The World Animal Protection charity has said 40 billion chickens live in overcrowded factory farms all around the world.
It said they are often crammed into sheds with up to 10,000 other chickens.
On average, most of them will have a space smaller than a piece of A4 paper to live in.
While many will spend their lives "suffering discomfort and pain" caused by growing too fast.
Looking at three criteria - policies, targets and reporting - it has given each company a grade, from 'failing' to 'very good'.
On Domino's PLC (across the EU and UK) it said the company has a global animal welfare policy but is "weak on chicken welfare."
It also has no targets to improve chicken welfare, and publishes very limited data on its progress.
Nando's, the report said, has not made "robust commitments" to improve chicken welfare, only has some country-specific targets and publishes very limited data on its progress towards better chicken welfare.
On McDonald's, it said the fast-food giant has made several commitments to improving chicken welfare, but they do not align with best practice.
"Despite McDonald's having a target to avoid broiler cages across all geographies, they do not have any other truly universal or robust targets."
It said Burger King's parent company has made robust commitments to improve chicken welfare in the US and Canada, but not in other countries.
While coffee giant Starbucks has made robust commitments to improve chicken welfare in the US, but not elsewhere.
Subway has also made robust commitments to improve chicken welfare, but not outside of the US market.
While KFC has made commitments to improve chicken welfare, the report said "these are not robust enough."
KFC only has some country-specific targets that are limited in scope, and publishes very limited data on its progress.
It said the results show "an almost universal disregard" among the brands within their policies, business targets and objectives for improving the treatment of chickens throughout their global supply chains.
"The modern meat chicken has been developed through extreme genetic selection. Each chicken is expected to reach its slaughter weight in around 40 days - a weight it would naturally take around three months for chickens to reach", the report said.
"This rapid growth can cause severe health problems including painful lameness, because the chickens' legs cannot support their rapidly growing bodies, and heart and lung strain."
"These health problems mean the animals often spend much of their lives sitting down and are in constant pain from their lameness."
It has also criticised the use of cages and unnatural lighting.
On cages, it said: "These barren systems severely restrict movement and behaviour and involve even more extreme overcrowding.
"Consumers are already clear that cages are unacceptable for chickens as a result of campaigns against the caging of egg-laying hens."
On lighting, it found: "Most chickens spend their whole lives in closed sheds without any natural light. Lights are left on for long periods to encourage rapid growth, often with only a short period of darkness.
"This practice stops the chickens from resting and developing naturally, which increases their stress levels and susceptibility to panic."
Read the full report here