McDonald's has topped a global ranking of farm animal welfare standards among fast food chains but still has "a lot more work to do" to reduce the suffering of factory chickens, according to a report.
The fast food giant beat KFC, Burger King, Subway and Starbucks in the sixth Business Benchmark on Farm Animal Welfare (BBFAW) ranking of 110 global food companies.
No fast food company achieved the top "tier one" status in the ranking but McDonald's, which feeds 68 million people every day, ranked towards the top of tier two after making farm animal welfare a part of its business strategy.
Waitrose, Marks & Spencer and The Co-operative Group all achieved tier one ranking.
However KFC, Pizza Hut and Starbucks could only manage tier five, defined as showing limited evidence of implementation, while Subway and Burger King both ranked in tier four, defined as making progress.
McDonald's commitments to animal welfare have included sourcing eggs from cage-free hens in the UK, Europe and New Zealand and sourcing higher welfare pork in the UK, and has said it aims to phase out cages for pregnant pigs in the US and source cage-free eggs in the US, Canada and Australia.
However, World Animal Protection, which compiled the rankings, said McDonald's, like other businesses on the list, still had "a significant way to go to improve the welfare of the millions of chickens served up in its restaurants around the world".
World Animal Protection chief executive Steve McIvor said: "It's clear that fast food companies can no longer afford to ignore animal welfare. Consumers are showing that they increasingly care about the welfare of animals when they are deciding where to eat.
"McDonald's have made some strides to improving conditions for farm animals in certain markets.
"However, like other businesses on the list, they still have a lot more work to do to reduce the suffering of factory farmed chickens, who live in conditions that are totally unacceptable.
"Like any other animal, chickens must have the chance to live decent lives, free from pain and stress."
He added: "Our aim with this report was always to encourage better disclosure of companies' standards, which will encourage others to act."
A McDonald's spokesman said: "We believe that our outcome-based approach provides the most comprehensive, animal-centric way forward to measurably improve chicken welfare.
"We are currently working to establish a global, multi-stakeholder advisory council to inform our ongoing chicken sustainability efforts, inclusive of welfare."