Experts say the rare phenomenon is just a quirk of nature and can occur if the chicken receives a shock during egg production.

农业专家们也表示，这样罕见的情况实则是大自然的一种变异，如果母鸡在生蛋时受到惊吓，就可能产下异常的鸡蛋。

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This begins with a stimulus, such as an electric shock, that promotes the fusion of an egg cell that has had its nucleus removed with a donor cell whose nucleus it will assume.

ECONOMIST: Cloning around

Because the theory relies on an object that itself has already found a way to grow to the size of Mars, the bow shock idea creates a bit of a chicken or egg problem.

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