Mum makes a shock discovery when opening a carton of eggs.

Eggs are already pretty awesome. They’re a great source of protein, healthy fat and 11 different vitamins and minerals.

But every now and then Mother Nature decides to make a hen’s egg just a little bit more special – by giving it a double yolk.

There’s nothing wrong with the relatively uncommon phenomenon of double-yolked eggs (which occurs for about every 1 in 1000), but they had one shopper freaked out when she purchased a dozen this week.

A Coles brand free-range carton that Queensland mum Mariana MacLeod‎ picked up from her local supermarket contained not one, but NINE double-yolked eggs.

The shocked mum posted an image of a bowl full of double yolks on Facebook along with a message to Coles.

(Image via Facebook.)

"Did I just win the food lottery or is there something seriously wrong with these Coles eggs - 9 out of 12 eggs were doubles?!!"

"Kids and I are too scared to eat them - but Google says they're perfectly safe and a sign of luck."

Mariana added she was buying a lottery ticket to try to capitalise on her luck - which might sound like a savvy idea, but according to ABC resident science expert Dr Karl Kruszelnicki, this isn't wise.

Dr Karl gives a far more detailed explanation that can be found here, but basically, the fact that young hens are more likely to produce double yolks and hens producing eggs for the same carton are likely to be around the same age, plus that 'extra large' eggs like the ones Mariana MacLeod purchased are also more likely to be doubles, makes four or five double-yolked eggs not as uncommon as you'd think. (He didn't say anything about nine though.)

As for the safety of the eggs, Coles assured the mum the eggs are "perfectly safe to consume" but offered her a free refund or replacement if she was unsatisfied.

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