No yolk: This chick lays double-shelled eggs

Something unusual is hatching at the home of A.C. and Olivia Crooms.

The Jacksonville couple was in for a surprise when they discovered that one of their hens was laying double-shelled eggs, which contain one yolk and another shelled egg all inside of a larger shell.

"I went in my chicken coop, as I usually do, one day and I looked on the inside and I saw this large egg," Olivia said. "I was excited and I asked where it came from and said it can't be the hen. It looked like it could have come from a goose or a peacock.”

A.C. and Olivia, who both were raised on farms, said that it is a rare occurrence and have no explanation as to why or how this happened.

“I’ve seen an egg with a double yolk before, but I’ve never seen another shell inside of an egg,” A.C. said. “I’ve been around chickens for 65 years, and I’ve never seen this before.”

So far, the hen has laid four double-shelled eggs, each measuring three-and-a-half-inches long and seven-and-a-half-inches round, double the size of a standard chicken egg.

The Crooms have raised a variety of prize winning birds at their Jacksonville home for more than 60 years, including chickens, peacocks and doves. They sell brown eggs from their standard cochin hens. One of the hens, who they have named “Whitey,” was unique from the start — she was the only survivor of four white chicks born to black cochin parents.

“She hatched last year around June,” A.C. said. “She started laying eggs around 6 months ago, but she was only laying regular eggs.”

But a few weeks ago, the Crooms noticed a marked change in the size of Whitey’s eggs. The Crooms carefully observed her after that first enormous egg and were amazed by the outcome.

“She laid these eggs every other day; so she laid 8 eggs in 9 days,” A.C said. “Unless it was from something started down her bloodline, I don’t know why this happened.”

Ken Anderson, an N.C. Cooperative extension specialist and professor for North Carolina State University Department of Poultry Science, said the occurrence stems from a problem with muscle contraction in the reproductive tract.

“It causes an egg to move backwards into the reproductive tract and then begin part of the egg formation again,” he explained, “and that's where the second shell comes in."

Anderson said that he has seen double-shelled eggs before, but it is especially rare for them to come from one hen within a short period of time.

"I've been around for 44 years in the egg industry and I've seen half a dozen of them, but that doesn't mean there aren't more occurrences,” Anderson said.  “Most of the time they won't it make it out of egg selection without breaking. I've seen it in all kinds of chickens, but most of the time they'll be found by people with small farms mostly because they hand collect them."

The Crooms, who cracked two of the eggs to make sure that they were double shelled, plan to hold on to the remaining eggs to show anyone interested in getting a glimpse of what Olivia describes as “miracle eggs.”

A.C. guaranteed that there is no secret formula or method in getting a hen to lay double-shelled eggs, and he doubts Whitey will produce any more in the future.

“You probably won’t see that anymore from her, but maybe down through her generations,” A.C. said.