The US Department of Agriculture's current rules require organic livestock to spend time outdoors where they can engage in what the agency calls ‘natural behaviour’. The rules do not specify how much space the animals should have or what it should be like.

Some organic farmers give their hens time to scratch and peck in pastures. But on many big farms, the hens spend their time in the fresh air on concrete patios and in other enclosures.

Mark Kastel of The Cornucopia Institute says that is not what consumers have in mind when they buy organic eggs.

A USDA spokeswoman says it has not yet decided whether to take up the matter, reports Orlando Sentinel.