The US Department of Agriculture (USDA) on Wednesday issued long-awaited final regulations to standardise living conditions of organic livestock and require that chickens raised organically have regular access to outdoor pasture, Reuters reported. 

The rule will close loopholes that allowed some organic egg producers to meet outdoor access requirements for organic egg-laying hens with open-air porches, rather than pasture.

"It's fair to say that this is the most significant update in organic regulations in over 30 years," agriculture secretary Tom Vilsack said on a call with reporters.

The USDA received more than 40,000 written comments on a draft version of the rule, Vilsack said, many dealing with the provisions that dictate minimum indoor and outdoor space requirements for livestock.

Producers must comply with the rule within a year, but have five years to comply with certain provisions like the outdoor access requirement for laying hens.

A 2016 attempt at similar regulations under the administration of former President Barack Obama was withdrawn in 2017 by his successor Donald Trump.

Democratic Rep. Chellie Pingree of Maine said on the call with reporters that organic producers would be relieved the lengthy rule making process is coming to a close.

"I'm very excited to be able to say, ‘finally'," Pingree said.

Regardless of labels on egg cartons, organic chickens in the US and Europe were moved indoors in spring of 2022 as a historic outbreak of avian influenza threatened flocks worldwide.

The US on Oct. 4 confirmed its first case of avian influenza on any commercial poultry farm since April in South Dakota. Since then, Minnesota and Iowa have reported their first outbreaks in commercial flocks since last winter.