Residents living nearby told local media that that they were woken in the middle of the night by the sound of a loud explosion at the plant at Stoke Ferry, near Downham Market.
But a company spokesman said: "There was a minor explosion in a boiler. It was contained within the boiler and at no time was there any risk to the public.
"The feed mill has people on site 24 hours-a-day, there was some minor damage to the building."
The spokesman added that a full investigation was now under way.