On average from pipping, how long before baby appears?

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I seem to have so many little issues this year i have never had before

On average, from when baby starts pipping, how long should it take baby to break free from the shell?

At what point should i intervene and assist them?

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Was worried as my 3 eggs started pipping midday monday, and by yesterday sound from within had gotten very soft, but 2 pushed out on their own, 3rd i gave a bit of help as it was stuck in the oddest positions with both its legs and one wing over its head, its alot weaker than the other 2, but surviving for now, so im very pleased...

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What i meant was it was stuck, it had dried in that position, obviously with our weather, there wasnt enough humidity, once i had misted the box and the egg, he managed to start unsticking itself from itself basically, its a bit weak but seems to be doing ok so far.