Australian shoppers are putting free-range eggs in their trolleys, but not free-range chicken meat.
And scientists suspect it is because of our own psychological bargaining.
Nearly half of all eggs Australians buy are free range, but less than 20 per cent of all chicken meat sold is free range.
Researchers believe one reason for the discrepancy is "moral licensing", whereby when we do something good, our brains give us licence to do something "bad".
When we buy free-range eggs, we're giving ourselves moral licence to buy non-free-range chicken meat, says behavioural economist Professor Lionel Page from the Queensland University of Technology.
Our brains find ways to lie to us - or, at least, make us feel better about our decisions. It's one of the ways scientists try to explain what University of Sydney PhD researcher Amelia Cornish calls the "welfare gap" - the gap between how much we claim to care about animal welfare, and our actual purchasing decisions.
When surveyed, a significant number of shoppers say they will happily pay more for free-range eggs. But then, for some reason, many of those same shoppers walk out of the supermarket with caged eggs.
"Australia is an animal-loving nation. But that's not reflected in purchase decisions," she says.
"When you ask people in surveys ???would you pay more for free-range', it does not cost anything to say you would.
"You might want to give a good impression to the person asking the question. You might even want to believe it yourself. And it costs nothing to say it."
Ms Cornish says strong campaigns by animal activists about the living conditions of cage chickens has played a part, too.
"Animal advocacy groups have really hounded egg welfare. Knowledge about laying hens is significant higher than for meat chickens, cows, sheep and pigs. You have to deduce that knowledge is leading to better choices."
Australians now buy almost as many free-range eggs as cage eggs; in 2009, only 5 per cent of all eggs sold were free-range.
She plans to test her hypothesis with a new study and is recruiting participants to determine what impact free-range labelling has on consumer purchase decisions.
But she admits that cost also plays an enormous role.
The averaged dozen-pack of free range eggs costs about $5, while caged eggs cost about $3.
But cost disparities in meat are much bigger. Coles' breast fillet, for example, costs $9 per kilo, while free-range Lilydale breast fillet sells for $18 a kilo.
In studies by Meat & Livestock Australia, the most important factor in a meat purchase decision is price, followed by freshness and country of origin. Animal welfare comes in fifth.
The organisation surveyed shoppers about purchase decisions, and then followed them to see what they bought. It did not matter what they said, says MLA chief marketing officer Lisa Sharp.
"When we followed consumers to the shelves, time and time we saw that price was first."
However, University of Melbourne animal welfare expert Professor Christine Parker argues that the boom in free-range egg sales has not come from increased consumer awareness. He claims it is the result of supermarkets putting pressure on egg suppliers to dramatically cut the price of their free-range product.
"You say ???why should I pay double for free range?' When, of course, you could easily afford to pay way more. But food is pretty cheap. It's more a perception that it's expensive," she says.
"People are concerned that animals are suffering. But we're stuck in this system where we think food should be really cheap, so we find it hard to pay more."
As an economist, Professor Page is even more pessimistic.
"Economists say you have to always remember that people follow incentives. If you cannot cut the difference in price, I'm not sure there is a silver bullet to get people to change."
The story Chicken or the egg? Why free-range eggs 'win' over free-range chickens first appeared on The Sydney Morning Herald.