Jeremy Hobson: Burger King is going to become the first big fast food chain to go cage-free. In five years, the chain says all of the animals from which it gets its eggs and pork will be labelled cage-free animals. What exactly does that mean?

Here’s Marketplace’s Jeff Tyler.

Jeff Tyler: The most common eggs sold in this country are called conventional eggs. Those hens require the least space. Matthew Prescott with the Humane Society of the United States explains.

Matthew Prescott: You’ve got, for example, five to eight chickens living in a cage the size of a file cabinet drawer for their entire lives.

‘Cage-free’ eggs come from hens moving about in, say, a barn. ‘Free-range’ chickens get access to the outside. And organic eggs come from hens on a special diet. So Burger King’s move is a small step, but significant.

Prescott: Simply getting chickens out of cages means a huge improvement in their wellbeing.

It comes with a cost. In Georgia, David Lathem raises both conventional and cage-free eggs.

David Lathem: The housing cost is much more expensive for cage-free than conventional housing.

That’s reflected in retail prices. Cage-free eggs cost about three times more than the conventional kind.

I’m Jeff Tyler for Marketplace.