Why don’t eggs from the grocery store hatch?
That was the question of the evening. Is it because they’re refrigerated? Or because they’re unfertilized? Or some other reason? If they’re unfertilized, why would hens lay unfertilized eggs? It seems counterproductive from an evolutionary perspective.
Here’s what Wikipedia has to say:
Most commercially produced chicken eggs intended for human consumption are unfertilized, since the laying hens are kept without any roosters. Fertile eggs can be purchased and eaten as well, with little nutritional difference. Fertile eggs will not contain a developed embryo, as refrigeration prohibits cellular growth for an extended amount of time.
So, technically the answer is both, but practically it appears that the typical egg purchased from the grocery store is unfertilized. But that doesn’t answer the second question: why would hens lay unfertilized eggs? Do they always lay unfertilized eggs, like fish, which are then fertilized later? Or are they fertilized through “the usual means” if a rooster is present, with the hard shell formed later but before the egg is “birthed”?
Google tells me that, “When a rooster mates with a hen, the semen is stored in the oviduct for later use. When she gets ready to lay the egg, a sperm fertilizes the egg before the shell surrounds it. The sperm is viable for about a month in the oviduct.” That also explains why chickens lay unfertilized eggs if there’s no rooster around—I can’t imagine in the ancestral environment that a typical hen would ever go a month without seeing a rooster, so an unfertilized egg would be rather rare.
Apart from the ancestral environment, it’s worthwhile to note that, like most domesticated flora and fauna, chickens have undergone significant genetic engineering (through selective breeding) throughout the generations. The Leghorn, for example, which produces the vast majority of the world’s white eggs, has been bred to lay an egg every day like clockwork. Wild chickens probably wouldn’t have fared very well under such circumstances, but it certainly serves domesticated chickens’ genes well.
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ゲイの鶏っているんでしょうか？
Human women ovulate about once a month… if you think about it, it’s basically the same thing (although most people would probably feel somewhat revolted at the idea)
We have 2 hens that have been laying on (roosting?) their eggs – 1 for 24 or so days – the other about 2 weeks. I know that the gestation is typically 21 days so would a hen ’stay on’ an egg or eggs for this amount of time if they are not fertilized? Usually, all of our hens do NOT stay on their eggs (thus we gather them) but now 2 are but no baby chicks? Is at least one of the hens confused or have I somehow miscounted days?