Dry Incubation **NOW WITH PHOTOS!** - How Low is Too Low? 10% Humidity**ANSWERED: NO.**

[AllenWMiller]

I should also discuss Chad's early hatch. This is not a good thing, except perhaps for certain bantams. If you are hatching standard chicken eggs then your eggs didn't hatch early due to humidity levels but because you are running your incubator too hot. Early hatches reflect too high temps and late hatches reflect too low temps. Also when your chicks finish absorbing the yolk through their navel I think you may experience rough navel syndrome where a hard crust is stuck to the area. The chick may even develop a navel infection. This is a result of too low humidity and too high temperature. Hope I'm wrong on this however.

Also remember that an early hatch means the chick has not developed fully. Doesn't mean the chick won't grow up healthy on the outside but this can lead to genetic issues in future generations.

 

[AllenWMiller]

A few more points on incubation:

Store hatching eggs no longer than 7 days between 40-65f (55-60f is optimal at 75% relative humidity).Remember that cell division in the egg occurs at 67f and above. The first cell division is completed about the time the egg enters the isthmus. Additional cell divisions take place about every 20 minutes; so, by the time of lay, several thousand cells form two layers of cells called a "gastrula." Once the egg is laid it cools and cell division slows or stops until proper environmental conditions are met.

Also remember the day you are setting the eggs in the incubator to allow the eggs to set in the hatching room for 4 to 8 hours to warm up to the relative room temperature of 70f and 70% humidity. This will prevent the cold eggs from sweating in the hot incubator.

One of the biggest failures in a foam hobby incubator is the lack of proper ventilation during the hatching process; particularly with automatic turners. We assume that since the eggs are being turned this is sufficient to tending the eggs. But as the embryo is developing it is taking in oxygen through the pores of the shell and likewise it is expelling carbon dioxide through the shell into the incubator.

If we allow the unit to remain closed for days this is tantamount to asphyxiation and is often the reason for a poor hatch. We must open a foam incubator several times a day albeit it briefly to exchange the air in the unit.

Prior to automatic turners for these small units we naturally opened them twice a day to turn the eggs. One time this rule should be suspended is during a power outage. In this case the unit should remain closed to conserve heat and humidity. The other time this rule is suspended is from the 18th through the 21st days when we stop turning the eggs and close the unit for hatching.

 

[AllenWMiller]

Below is a standard hatchery chart for solving incubation problems that I've used since childhood:





Indications



Possible Causes



What to do



No blood vessels
at candling

Eggs not fertile



Check flock management
Embryo died very early



Check egg holding conditions
Check incubation operation



Many dead embryos

Temperature too high or low



Check incubator and accuracy of thermometer
Improper turning



Turn 3 times per day
Poor oxygen supply



Increase ventilation
Poor nutrition



Check breeder flock diet



Piped eggs not
hatching

Low humidity



Have correct wet bulb temperature



Hatch too early

High temperature



Check temperature



Hatch too late

Low temperature



Check temperature



Shells stick to chicks

High humidity early
or low humidity late



Check humidity



Cripples

Temperature problems



Check incubator
Humidity problems



Check incubator
Improper turning



Correct turning
Smooth hatching trays



Provide better traction



Large, soft-bodied
weak chicks

Low temperature



Check temperature
Poor ventilation



Improve air flow



Mushy chicks,
dead on tray

Navel infection



Improve sanitation



Rough navels

High temperature or wide temperature fluctuations



Check temperature
Low moisture



Check wet bulb temperature

 

[[email protected]]

one reason low humidity might help is the air sack will be bigger so the chick will have an essayer time getting to the air sack and more oxygen.

 

[chickensinwasillaAK]

The 20% minimum is if you're using a forced air incubator. If you want to try something fun, come up to Alaska and hatch in the winter. The air is so dry getting to 60% during lockdown is quite the task. I figure the folks in Arizona experience the same thing (but at a warmer overall climate.)

ChooksChick,

Thanks so much for this info on dry incubation. I really appreciate your willingness to share your knowledge.

One question - in the beginning of your instructions you say to completely ignore humidity but the last paragraph in Q&A says to not let the humidity drop below 20%. Is this just for the last few days?
I'm asking because my hygrometer - before adding eggs - reads 10%

Kerri in NC

 

[AllenWMiller]

You are somewhat correct Tyler, the air sack will be bigger if you hatch i low humidity..But...You will also make the membrane tough and dry and as a result could make it more difficult for the chick to break it to get into the air cell. You will also be drying the chick out too much inside the shell which can lead to leg and even wing malformation.

As I stated earlier humidity is one of the four cornerstones of incubation and the levels of humidity I described in a previous post are not some random numbers I've came up with but numbers/rules that have been long established over a century. I agree you can hatch chicks under these "new" low humidity levels and you may get good results. But again, you are risking the health of the chick and its ability to pass on strong genetic material to future generations not to mention the bird's own longevity.

And I agree with ChickensinWasilla you do have it tough keep high enough humidity in Alaska and yes I've friends in Arizona that have a similar issues with dry air keeping humidity up during the hatching cycle. If you are using a small foam incubator or even a small hobby incubator and find it difficult to keep humidity levels up, soak three medium sized sponges in water and place them stacked up in the center of the unit before you close up for the hatch cycle. Put a drinking straw through a vent hole onto the top and make contact with the top sponge. As the humidity drops you can continue adding water through the straw to saturate the sponges. (Oh and if the humidity should get too high remove a sponge. Yes you can open a hatcher during this cycle albeit briefly and quickly without harming the hatch. After all even a brood hen will leave her clutch occasionally during the hatch with no detriment to the hatch.)

Cheers

 

[AlienChick]

WOW! I've learned so much from this short thread.

Thank you, Allen, for the info. I use a styro incubator and was very interested in what you wrote about not opening the 'bator to allow for air exchange. I have an auto turner and never thought to open my incubator unless I'm candling on day 10. Eventually, I'll be buying an incubator cabinet . . . like a Sportsman, but right now I'm still saving up for it.

Also, Allen, I'm curious as to what type of incubator(s) you are currently using, if any?

 

[[email protected]]

some one should see what the humidity is under a chicken.

 

[AllenWMiller]

AllenChick I use Petersime and Jamesway incubators and hatchers. I used to teach 4-H and have past experience with foam incubators like the hovabator. I also use the Old Sportsman Incubator for quail and small batches when I don't have enough to turn on the large incubators and hatchers.

Tyler that's a good point and oddly enough I did test the humidity under a number of brood hens as part of my thesis work back in the old days at Cornell.

I can tell you that old timers didn't just come up with their humidity and temperature numbers out of thin air. There is a good deal of data from the late 19th and 20th centuries demonstrating poultry-men "testing" these two factors under brood hens. Their results matched my results for my thesis almost perfectly. And yes a brood hen will maintain humidity levels as mentioned in previous posts. And yes I did strange things as a youngster and young man that included putting hygrometers and thermometers under a lot of brood hens and checked them regularly.

Again oddly enough I'd like to repeat these tests today with modern equipment and put a computer aided test package under their nests that would continuously monitor temperature, humidity, how many times a day the brood hen gets up or off the nest to cool it, etc. I think even now the results will still be similar even with modern equipment.

 

[Jeffross1968]

Question I have...with the sportsmans, I've seen people doing staggered hatches...placing a shelf of 90 each week. The bottom is a hatcher, correct? Moving the oldest to the hatching shelf each week. So...how does humidity work with this? I'm guessing the humidity would have to be somewhat constant for staggered hatch. How can that work?