Fire investigators are trying to determine what caused a devastating blaze that killed thousands of hens at an egg farm near the airport.

The blaze broke out around 1:30 p.m. Tuesday at Sparks Farms, about 13 km northeast of Calgary.

The farm was purchased by the Gilani family in 1976.

The family run business lost 4 barns and thousands of egg-laying hens in the fire.

About two dozen firefighters from several districts battled the blaze.

Crews were able to save the plant's egg sorting building.

About 80 employees were working at the time and fire officials credit the farm's fire plan for a quick evacuation.

Fire officials are still not clear how the fire started or exactly how many chickens died in the blaze.

The barns can house up to 30,000 hens.

The family is devastated by the loss but say they are dealing with it the best they can.

They hope to have the egg grading facility back up and running in the next few days.

The farm handles about half of the province's egg production and processes eggs from over 80 producers.