Up to 60 firefighters fought to control a major fire at a chicken hatchery building south of Auckland, putting it out on Saturday night.
The blaze was at Bromley Park Hatcheries, in Tuakau. It was discovered by a worker, coming from the roof.
Fifteen appliances battled the fire since about 3pm on Saturday.
A Fire Service spokesperson says crews are now dampening down hot spots, and will remain at the scene overnight, to ensure it does not start up again.