SALEM — Gov. Kate Brown signed a bill Monday requiring cage-free eggs in Oregon.

The law mandates that commercial farms with 3,000 or more chickens give their birds room to move around and stretch their wings. By 2024, all eggs produced or sold in the state must come from cage-free hens.

The Humane Society of the United States called the new law a “monumental win for hens confined in tiny cages in the egg industry.”

Oregon joins a handful of other states that have passed similar laws, including California, Washington and Massachusetts. The Oregon requirements will give some 4 million birds added space, as well as perches.

Cage-free laws provide an improvement for chickens’ well-being — in many cases a significant improvement. But most of them still will be kept in relatively small spaces. The news website Vox called Washington state’s recent law, which is similar to Oregon’s, “a start on the path toward humane conditions.”