The couple from Lower Saxony raises chickens as "a hobby" and found an egg weighing 184g two weeks ago.
An ordinary chicken egg weighs on average 50g, meaning the farmers' discovery is more than three times bigger than a normal egg.
The largest egg worldwide weighed 454g and was registered by the Guinness Book of Records in the United States in 1956. The newly found egg is presumed now to be the biggest after the midcentury record-breaker.
The nearby Museum of Natural History in Braunschweig wants to display the egg in an exhibition.