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incubation humidity:getting it right
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incubation humidity:getting it right,anhui regal electronic technology co., ltd.-3d捕鱼游戏

a dvice on incubation humidity varies wildly from different sources and it seems to be a constant worry to newcomers who are incubating their first few batches of eggs.

when incubating eggs and hatching chicks, there are always far more failures caused by the humidity having being too high so why is this?

first let's consider the ‘perfect’ case

eggs have porous shells and during the incubation process, a certain amount of moisture is lost through the shell. as the weight of the egg decreases, the air sac at the blunt end of the egg increases.

by monitoring the size of the air sac through candling, the correct weight loss can be achieved so that at the point of hatching, the membrane into the air sac is brittle allowing a chick to break through (this is called internal pipping) taking its first few breaths of air with minimal effort and reserving most of its energy for breaking out of the shell.

candling allows you to monitor the size of the air sac.

once a chick has absorbed the yolk sac, it is then ready to pip the external shell and by rotating around inside the shell, he (or hopefully she!) is able to remove enough of the shell to push its way out and hatch.

if the incubation humidity is too high

when the humidity is too high, less moisture is lost from the egg and as a result, the air sac is too small in size, the membrane is less brittle and much more rubbery. think of the air sack like a small balloon: once inflated, it’s easy to pop but while deflated, it remains thick and rubbery.

a chick trying to break through this membrane can expend too much energy, or can suffocate from a lack of oxygen before it manages to break through.

in addition to the difficulties a chick will have with internal pipping, if the egg hasn’t lost enough moisture, the chick cannot rotate inside the shell and becomes stuck. the fluid around it dries out once the chick has pipped making life even more difficult. unable to break free from the shell, it will eventually die.

so what is the correct incubation humidity?


for still air incubation,usually no water needs to be added but for forced air incubation (incubators with a fan that circulate the air around, trying to maintain a constant temperature throughout) then there are some guidelines given that generally state 45% for chickens and slightly less for waterfowl.

the reality though is that the porosity of eggshells vary (becoming more porous later on in the year) and vary between different breeds and with different thickness of shell, so the correct humidity is whatever achieves the correct moisture or weight loss from the egg which is generally somewhere between 11 and 13% when the air sack occupies approximately a third of the egg at the point of internal pipping.

the best way to do this is either by recording the weight of the eggs using some accurate scales,or more simply by candling your eggs and comparing the size of the air sac to a diagram that shows the ideal size on different days of the incubation period.

if the air sac is too large, the eggs are losing too much moisture and you need to increase incubation humidity and conversely if the air sac is too small, decrease humidity so the eggs can lose moisture faster.


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