A federal appeals court on Wednesday upheld a decision to dismiss a lawsuit by a farmer that challenged a law banning the inhumane confinement of egg-laying hens.

The 9th U.S. Circuit Court of Appeals affirmed the 2012 decision by a lower court to throw out the lawsuit by egg farmer William Cramer. Cramer's lawsuit said the law is unconstitutionally vague.

It's the third time courts have rejected lawsuits by egg farmers against California's landmark Proposition 2.

"We are thrilled that the court sided with the millions of California voters who supported this measure and chose to end extreme and reckless factory farming practices," said Jonathan Lovvorn, senior vice president and chief counsel for animal protection litigation for the Humane Society of the United States.

The initiative approved in 2008 bans the inhumane confinement of egg-laying hens, breeding pigs and veal calves in cages so small the animals cannot stretch their limbs, lie down or turn around.Since its passage, farmers have complained that the measure lacks specific language designating appropriate cage size and as a result puts them at risk of misdemeanor charges and fines up to $1,000.

In addition, they say they are on the hook for millions of dollars in upgrades but can't get bank loans without knowing whether new cages will be in compliance.