Animal welfare has been enhanced for laying hens and pullets following a programme of reforms.
The welfare code has been designed to "safeguard and enhance" the welfare to birds, according to Defra.
The strengthened statutory guidance is now in place for keepers and owners on how to meet the needs of their birds.
Bird keepers are now expected to provide a more enriched environment for all laying hens to enable them to display more of their natural behaviours such as foraging.
The codes also provide guidance on how to assess the welfare of birds, as well as on contingency planning to help ensure the welfare during any emergencies.
The codes will be used by enforcement bodies including Animal and Plant Health Agency (APHA) inspectors and local authorities when investigating allegations of poor welfare to look at whether animal welfare standards are being met.
Defra Minister for Animal Welfare, Lord Gardiner said the update reflects the latest advice from vets and animal husbandry developments.
"This code was carefully consulted on with industry experts, and uses the most recent scientific and veterinary advice to ensure this clear guidance provides the best advice to owners and keepers to help ensure the high welfare standards of their animals," he said.
The UK has some of the highest animal welfare standards in the world, with recent announcements including plans to raise maximum sentences for animal cruelty to five years and making CCTV mandatory in abattoirs.