Correct Humidity...?

[Elixafar]

I am hacting some eggs.I don't have much experince and don't know about the importance of air sac until, I learn about it frm BYC. The humidity was 55 to 60 % for fisrt 7 days and when i came to know about dry hacting, i decrease the humidity to 30 %. I weigh the eggs on day 10 and today is day 11.Eggs had lost about 10-11% weight. So, the question is should i need to increse or decrease the humidity or it should remain at where it is 30%…?

 

[ChickenCanoe]

Eggs should lose 11-13% by day 18 so it appears they may have already lost too much. If that is the case I would probably increase the humidity.
Do you happen to be at high elevation?
If it were me I would candle to see what the air cell looks like.

 

[Mellowmalt]

what you have to remember is that temperatures need to stay steady. Humidity can vary greatly. If you research lab results on different humidity it has been shown that if the chick loses too much moisture then it becomes weak and shrink wrapped and hatch problems increase.
If humidity is too high then chicks are born wet.

So you have to ask yourself would you prefer chicks born wet or chicks born dead.

But you might be saying, but everyne is toutng dry incubating as the latest craze. Yes and clearly it works but if it doesn't wok the consequences are fatal!
So you should realize that dry incubating is not something you should aim for on your first attempt, it should be used if you previously had problems.

There are too many variables that will influence what humidity you need. For example take a bantam egg over a regular egg, a bantag egg weight about 26g to a 50g large egg. Eggs need to lose 13% humidity in their 21 days incubating so that is roughly 3.5g for the bantam eggs or 0.17g per egg per day.
But I found that eggs lose 0.05g in storage. So if you stored your bantam eggs for 10 days prior to hatching your eggs will have lost 10x 0.05g = 0.5g.
That might not seem like a lot but it is actually 3 days worth of moisture lost in an incubator (before you even start) so if you were to incubate these eggs that have already lost 0.5g at 30% humidity you would most likely lose them all to shrinkwrapping.

Most articles mention that eggs have different porosity, some hold moisture better than others - obviously this is going to affect what humidity you should use.

I find the people that use and advocate just one approach do not have the experience to know better, the people with the experience will know what worked one year might not work another year and no hatches should be treated like it will be the same (unless all the factors are kept the same like breeders will have it down to a regular routine)

Ventilation is quite important as you can have the right humidity reading but things are too stuffy causing condensation to form - if condensation forms no matter what your sensor is showing humidity will be way too high. In that case it is more likely that the sensor is inaccurate which happens more than people realize with cheap ones. Use your equipment as tools to help, but don't rely on them without question.

Like someone said recently, if you candle your eggs to check humidity loss and you discover your eggs have lost too much moisture it is hard to put that moisture back but if the eggs have not lost enough, then humidity can be run dry for a few days to compensate.

The most important thing to remember and I feel beginners overlook this is that people that open their incubator to candle regularly, if you hand turn or if you only have a few eggs in the incubator then humdity should be run higher to compensate.

If you are incubating 100+ eggs in an incubator (remember each egg transpires 0.3g per day so your 100 eggs are transpiring 30g of moisture per day. Pumping that into your incubator even. You won't need as much in your humidity tray and if everything is tightly packed in the incubator you might not need any additional moisture at all.

Beginners then read this and go aha the professionals do it like this....

And that is where it all starts to go wrong...