HUNDREDS of factory farmed rabbits have died in the heat or been killed by foxes after a group of people let them loose.

Investigators believe several people broke into an unlocked shed at a Ballan Rd property sometime between 6pm on January 10 and 6am on January 11, the Geelong Advertiser reports.

The shed holds about 1200 captive rabbits in cages and several hundred of the animals were let loose, they said.

Owner Charlie Iliopoulos said he believed animal rights activists were to blame for the latest incident. His 66ha property has been broken into numerous times over the last four months.

He said after 40 years in the business, he was well aware intensive farming was often controversial.

But because the rabbits were unfamiliar with how to survive in the wild, hundreds had died, he said.

"Intensive farming is what it is. These people come in and take video of only the sick animals, which might be 1 per cent of what we've got, and make it look horrible. Yet they've let these rabbits out on a 40C day, subjecting them to hour upon hour of no water," he said.

"That's what really annoys me.

"I had to call in friends and spend about eight hours chasing the rabbits and putting them back in cages, and you can imagine how unsuccessful that was."

An incensed Mr Iliopoulos said he'd returned to the farm the following day to find what he described as a "sea of dead rabbits".

"These rabbits aren't wild and don't know how to run from a fox, so they just get killed. And the fox then moves on to the next one and the next one," he said.

"They just killed everything they could find.

"I look after these animals better than I look after myself - that's how I pay my bills, feed my family."

Animal Liberation Victoria founder Patty Mark rejected claims animal activists were to blame.

"We've had nothing to do with this. No activist I know of would release animals on a 40C day," she said.

"ALV is 35 years old and do heaps of open rescues, even rabbit rescues in the past. But under no circumstances would we release them into something like this - it's just not what we do."

Detective Senior Constable John Digby said police were still trying to identify those responsible.

"We are aware one female was caught inside the shed back in November, but at this stage we're still investigating the latest matter," he said.

Anyone with information about the incident, or who saw anything suspicious in the area, should contact Geelong police on 5225 3100 or Crime Stoppers on 1800 333 000.

Read more at the Geelong Advertiser.