"The Prevention of Farm Animal Cruelty Act" would mean that laying hens, pregnant sows and veal calves would be given more space and a larger environment in which to live.

According to the Humane Society of the US (HSUS), a sponsor of the measure, the Act will provide the most basic protection to nearly 20 million animals confined in industrial factory farms in California "that they will merely be able to turn around and extend their limbs".

If approved in November, the Act will prevent California factory farms from confining animals in battery cages for egg-laying hens. The new law would take effect in 2015.

However, the Sound Farm Animal Agriculture group have a different view on the initiative: "This measure is primarily an effort to ban the use of a scientifically proven method for housing egg-laying hens. If implemented it would trigger unintended consequences which are likely to include increased farm costs, decreased in-state production and higher egg prices for California families. There could also be significant environmental and food safety impacts," said the organisation, according to United Egg Producers Certified.

"California egg farmers already employ a variety of methods of housing egg-laying hens, including conventional housing, cage-free, free-range and organic. This market-driven diversity provides consumers with choices that inform sound farm practices."