Fourteen-year-old Tyler Seidel was making scrambled eggs when he cracked an egg containing not one but three yolks.
"It was pretty much a normal day, then I picked up this huge egg, went inside, cracked it open and three eggs came out!" Tyler said.
"I was very surprised when I saw that.
"I've had multiple doubles, but not a triple."
The "palm-sized" egg came from one of the free-range brown hens on his family's farm at Wandearah East, in South Australia's mid-north.
"It would've hurt it," Tyler said.
His mother was also surprised by the cracking find and suggested he take a photo.
After that, Tyler proceeded to add another egg and continue with the scrambling process.
"It tasted like a normal egg," he said.
A 'triple-yolker'
Tyler's father, Graham Seidel, exclaimed "Golly gosh!" when he found out what happened.
"I've never seen a triple-yolker before," he said.
"All I can say is, poor chook when it laid it — it must've hurt."
Mr Seidel said nothing out of the ordinary that he could think of would have contributed to there being two more yolks than normal.
"I crush my own wheat and peas and then I'll then mix it in with some commercial chook food — homemade pellets and Red Hen," he said.
Mr Seidel said no-one had been sceptical of the find online because "the photo seemed to prove it".
"There have been a few people reacting on Facebook and they've been surprised," he said.
A one-in-25-million chance
The University of Sydney Poultry Research Foundation's Sonia Liu said there was "not too much information out there" about three-yolk eggs, but said the phenomenon was "extremely rare".
"I managed to find some data from the British Egg Information Service suggesting a double-yolk egg is about one in 1,000 and a triple-yolk egg is about one in 25 million," she said.
"So that means in Australia, if every single one of us cracked one egg, only one of us would be lucky enough to see a triple yolk."
Dr Liu said it was most likely to occur in younger or older hens because of their changes in hormones.
Feed and housing conditions, she said, would not impact the chances.
"When one yolk reaches the correct size it will be released into the oviduct from the ovary and then they will be wrapped up with egg white," she said.
"Eggshell is actually the last thing to be added.
"A double-yolk or a triple-yolk egg is formed when two or three yolks are released too close to each other."
Dr Liu said the hen that laid the egg on Seidel's farm would have gone through a lot of stress.
"It's just like a human being giving birth to a very big baby," she said.
She said consumers buying eggs from the supermarket should not expect to crack a triple-yolker.
"All the oversized eggs would have been removed from the quality control process," she said.
