Even if the birds are not allowed outside, eggs produced in the EU could still be called free range.

If chickens are forced to be housed to reduce the risk of bird flu, the European Commission wants to scrap the time limit on the marketing of eggs as free range.

The UK has suffered the worst bird flu outbreak on record. More than 46 million birds have been culled on farms in Europe so far. There have been more than 100 outbreaks in the UK.

The end of the wild-bird migration in the autumn and winter months has led to a decline in the number of bird flu cases. In the UK and elsewhere in Europe, there has been an outbreak for a long time. In the UK, the order to keep birds indoors was lifted only in August, while in some parts of the Netherlands it has lasted more than a year.

A World Health Organization adviser says bird flu is no longer just a seasonal threat. The vaccine for chickens is not available at the moment.

Eggs can be marketed as free range as long as a compulsory housing order is in place and the farmers have been given longer and longer grace periods.

Three people in white hazmat suits pick up the corpses of birds as other birds fly overhead

National Trust rangers clear dead birds from Staple Island, Northumberland, where bird flu is devastating one of the UK’s most important seabird colonies. Photograph: Owen Humphreys/PA

After a 16-week grace period, free-range eggs had to carry a label stating they were "barn eggs", which is the term for eggs from hens kept indoors.

There have been fears of a collapse of the free-range egg sector if producers could no longer label their eggs as free range. Free range eggs were the majority of the eggs produced in the UK last year.

Farmers in the EU would not have to drop the free-range label on their eggs if there was an extended compulsory housing order.

There is a proposal from the commission that would need to be approved by the European parliament before it goes into effect.

Egg producers in the UK want the UK government to follow suit to prevent British suppliers from being undercut by EU imports.

Robert Gooch, chief executive of the British Free Range Egg Producers Association, said that the UK needs to align with the EU in the event of an Artificial Intelligence Epidemic.

The Department for Environment, Food and Rural Affairs is looking at how to respond to the EU. Get a monthly update on the biggest farming and food stories around the world by signing up for the Animals farmed monthly update. Send your stories and thoughts to animalsfarmed@theguardian.