Poultry in Wales will be allowed outside in a change to avian flu restrictions to allow keepers to maintain the free range status of their flocks.
The Welsh Government had ordered poultry stay indoors to protect them from a highly infectious strain of the illness.
But from Tuesday flocks will be allowed outside as long as keepers take risk-reducing measures.
Farming unions welcomed the move.
An avian flu prevention zone covering the whole of Wales was introduced last December after cases of the H5N8 strain were found in countries across Europe, including France, Germany and the Netherlands.
The original rules had prompted worries from NFU Cymru that the restrictions on poultry would damage the free-range egg and meat status of flocks.
The Welsh Government has now extended the length of the zone, which was due to expire Tuesday, to 30 April, but birds will be allowed outdoors under the condition that keepers employ a range of measures to reduce the risk of avian flu.
This includes regularly cleaning and disinfecting walkways and the fencing off and netting of ponds, and the use of dedicated footwear and clothing.
Keepers can also choose to either keep their birds indoors or keep them separate from wild birds, but all must fill in a self-assessment form to detail what they are doing to prevent their birds from getting the illness.
Chief Veterinary Officer for Wales, Dr Christianne Glossop, told BBC Wales the risk of avian flu had not gone away and there had been new cases since the restrictions were introduced.
"We are not in a position to completely lift the requirements, yet we are very mindful of the fact that we have been under these restrictions for 12 weeks now... We've learned a lot of things in that time," she said.
"We believe we understand the risks better."
One of the reasons for the change in regulations was because some poultry were not being kept indoors in "ideal circumstances", Dr Glossop said.
She said "simply keeping birds indoors will not completely protect them".
She added the Welsh Government was "trying to give our free range producers a way of continuing to protect their birds whilst maintaining their free range status".
England, unlike Wales, does not have a country-wide protection zone and restrictions only apply in high risk areas.
NFU Cymru and the Farmers' Union of Wales welcomed the measures.