Chicken eggs have long been included in daily diet of the person, but the chicken reproductive system, as in other animals, sometimes there are deviations in the embryonic period. Meet the egg formed inside the other eggs!
Incubation of one egg inside another is not a miracle of nature and not a trick, just a very rare natural phenomenon. The technical term for it sounds like a reduction in counter-peristalsis (counter-peristalsis contraction). The point is that one egg that has not yet fully developed in the reproductive mechanism of the chicken back into the bed, and the second is formed around it. Here’s how it looks in real life:
Under normal circumstances, chicken ovulidae and releases the ovum, which passes through the 5 divisions of the oviduct, by way of acquiring protein, support elements, and finally the shell that holds everything together and protects the contents from external influences. Sometimes on some of the stages fails, and then half formed egg leaves the hen, and the new begins to form directly on top of it.
In the end, a very large egg with labour pushed through the cloaca. Do not confuse this phenomenon with other, much more frequent when the formation of two eggs instead of one leads to the fact that eggs have two yolks — such an anomaly otherwise a nice bonus not name.