Bob Anderson, president of Burnbrae Farms, points out the collapsed remains of a barn that once housed about 40,000 chickens. ((CBC))

A massive fire at one of the largest egg farms in Canada has killed close to 40,000 chickens and caused more than $1 million of damage, fire officials say.

Investigators with the Fire Marshal's Officevisited Burnbrae Farms on Tuesday in Lyn, Ont., northwest of Brockville in an effort to learn the cause of the blaze that broke outbefore 11p.m. the night before, said Jim Donovan, fire chief for Elizabethtown-Kitley.

The barn housed about 38,000 to 40,000 chickens and was longer than a Canadian football field, Donovan said.

By the time firefighters arrived, about a fifth of the barn was engulfed in flames, he recalled.

Initially, a crew was sent into the barn.

"They basically stated on the radio that they could hear almost like a locomotive roaring above them," Donovan said.

The crew was pulled back out, and worked among the 56 volunteer firefighters, who fought for more than three hours to get the fire under control using two pumpers and seven tankers.

"It was a very stubborn, intense fire," said Donovan, who added that officials are hurrying to complete the investigation.

"You can appreciate the deterioration of the birds and then the stench and again insects and everything else," he said. "It's a very pungent odour. Obviously there was some manure that burned as well."

Firefighters saved 11 other barns

Bob Anderson, president of Burnbrae Farms, said the barn ravaged by fire has collapsed to almost a third of its previous height of about two storeys.

But he said the damage could have been a lot worse had the fire spread to the adjoining egg-collection building that grades more than a million eggs a day and is attached to 11 similar barns.

Anderson said the farm has conducted practise simulations with the fire department in the past.

"That training paid off big time in terms of the way they were able to fight this fire," he said.

He added that once the fire marshal's investigation is complete, the barn will be demolished and rebuilt.

In the meantime, he said the fire will not affect the company's ability to supply its customers, as it has other operations throughout Ontario and Quebec and also works with some independent suppliers.

The company supplies supermarkets, hotels, restaurants and other customers throughout the region.