It's dusk in northern Victoria and 30,000 rust-red hens are scratching in and around a 120-metre-long shed. Morning will find them settling on a nest box to produce an egg for Coles. But now the hot day is darkening - prime time for ranging free when you are a free-range chook.

But only about 5000 hens are outdoors. The rest are inside their home, one of six 30,000-hen sheds at Farm Pride's Bears Lagoon site, a major supplier of Coles' house brand free-range eggs. The media rarely see inside these sheds, but Coles has a story to tell about its new, and controversial, free-range standard.

Hen house: Farm Pride's managing director Zelko Lendich in one of the company's sheds at Bears Lagoon. Credit:Justin McManus

It smells of manure. Every hen, it seems, has something to say; it's a squawking ruckus. In the dusty light, no part of this giant shed seems bird-free; they cover the floor and flock on six levels of perches.

As Farm Pride's managing director Zelko Lendich says, there's no lady coming round to collect the eggs in a basket. It's automated egg collection. A conveyor belt removes manure. In six months, at 1½ years old, these birds will become, in industry parlance, ''spent hens''; their eggs too big for supermarket cartons, their laying rate no longer commercially viable. They'll be off to a slaughterhouse, a new flock moved in.