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Question:
We all know that a hen can lay 2 or more eggs at a sitting. We also know that an egg has room for one chick. This is my question. Can an egg hatch two chicks at a time? Is there a natural posibility for that to happen?


Replies:
It is quite rare for a hen to lay more than one egg at a sitting, but I have to agree - it is possible. It takes a day for the egg to be formed, and it is not possible for the egg to make two eggs at the same time (only one production line). A double laying can only occur if there has been a delay in laying one egg, so that a second one on the 'production line' is able to catch up. This might happen if the chicken is lacking in water, or suffering some other distress. As for the rest of your question - I will have to speculate a good deal. I have been raising chickens in the back yard for years, (although less now because my doctor says I need to cut down my cholesterol - so two eggs a day is out!!) Double yolked eggs are the result of two egg cells being shed from the chicken's ovary together, and they are not that rare - perhaps 1 in 50. If such an egg were fertilized, it COULD produce two chicks, but that is highly unlikely, as the two chicks would compete for the food in the egg, and both would be undernourished. Just before hatching the chicks need to poke their head into the air sac at the end of the egg. The air sac is not big enough for two - so there would have to be a struggle, and the loser (or both) would die. I have raised, and hatched, and eaten a great many eggs, and while I have seen many double yolkers, I have never seen twin chicks, and I have never seen a double 'failed to hatch' so I am assuming it must be pretty rare - on the other hand my friend Dr Karl has some interesting news on the subject -

http://www.abc.net.au/science/k2/moments/s409538.htm

Nigel Skelton


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