Eggceptional B.C. hen named Bell is laying eggs inside other eggs

The process known as counter-prestalsis contraction results in a regular egg being embedded inside a second, oversized one.

'It actually made me jump back, I was so in shock,' Dawson Creek hobby farmer says

Counter-peristalsis contraction occurs when an egg travels backwards inside a hen to become embedded inside another egg in the process of forming its shell. (Wendy Devuyst)

A chicken is producing rare eggs within eggs on a hobby farm near Dawson Creek in northeastern B.C.

Though not unheard of, the phenomenon is rare enough that most people go their entire lives without cracking open an egg only to find another one inside.

But now Wendy Devuyst has experienced it twice, thanks to an "eggceptional" hen named Bell.

The first occurrence was in January when she collected a "way larger than normal" egg from one of her approximately 75 chickens. It was "about two-and-a-half times the size of a regular-sized egg."

"I was thinking it was going to be a triple-yolker," she told CBC Daybreak North host Carolina de Ryk.

Instead, she cracked it open and, "Lo and behold, another fully-formed egg came out."

"It actually made me jump back, I was so in shock," she said. "I was like, 'How did that happen?'"

Watch the oversized egg being cracked:

A Dawson Creek chicken has been surprising its owners by laying oversized eggs that have another, regular egg inside. 1:28

The answer is a process known as counter-peristalsis contraction.

It occurs when a formed egg begins traveling backwards in a hen's oviduct and becomes embedded inside a second egg in the process of developing.

The second egg forms around the first, hence the large size.

Devuyst was more prepared on March 8 when she collected another oversized egg from Bell.

This time she filmed the process of cracking it open to discover another smaller egg inside, with her three children as witnesses.

"They thought it was pretty cool," she said.

Grégoy Bédécarrats, a professor at the University of Guelph's Department of Animal Biosciences, said it's difficult to track the frequency of counter-peristalsis contraction as eggs within eggs are eliminated during inspections at egg grading stations, but are not usually recorded.

He also said the phenomenon is likely caused by the hen's genetics affecting its egg-formation cycle, which would explain why Bell has produced more than one egg within an egg.

He also noted that while normal, it is relatively rare.

Devuyst said Bell seems to be acting normally and wasn't getting any special treatment, though she is now getting "extra treats" after laying two sets of double eggs.

"She is a real sweetheart," she said.

Bell is a Lavender Orpington chicken on a Dawson Creek hobby farm who has laid an egg within an egg — twice. (Wendy Devuyst)

For more stories from northern B.C., follow CBC Daybreak North on Facebook and subscribe to the podcast.