Category: Incubation

Maintaining high humidity in an incubator during hatch

Wet, new chickAround day 19, when the first chicks could potentially start to pip, it’s time to raise the humidity in your incubator to 65% or more.  High humidity during hatch is essential to lubricate your chicks as they do the hard work of wiggling around, pecking their way out of their shells.  At the same time, you need to keep the vent at least a third of the way open because these hard-working chicks need more airflow to feed their struggles.  But the open vent tends to lower the incubator’s humidity, so that’s the solution?

Increasing humidity in an incubator with a wicking clothYou can buy evaporating card to stick in your incubator’s wells, but the cheaper method is just to use a piece of cloth. If you place part of the cloth or evaporating card in the well and let the rest sit along the bottom of the incubator, water will wick up into the extra surface area, resulting in more evaporation and higher humidity.

For an even bigger dose of humidity to counteract the vapor lost when you open the lid, heat up some water until it’s steaming but is still just cool enough to stick your hand in.  I poured some of this warm water into the wells every time I opened the lid of my Brinsea Octagon 20 incubator, which meant that the humidity rebounded within a minute of me opening and then reclosing the lid.

Opening the incubator lidMost websites will tell you
to be as hands-off as possible during the hatch, opening the lid only once every six to eight hours.  Now that I’ve had a bit of experience, though, I disagree.  I’ve learned the hard way that if a newly hatched chick rolls a neighbor egg so that its pipping hole is facing the floor, the chick still in its shell can expire before you’re allowed to open the lid again. Knowing some tricks to maintain high humidity while still being allowed to open the lid seems to be key to higher hatch rates.

Incubating chicken eggs

After several rounds of trial and error, I figured out the best way to incubate chicks. You can browse through old posts, or splurge on my ebook for the more refined solutions.

Causes of chicken hatching problems

Day old chick

Our first trial hatch in the Brinsea
Mini Advance incubator
 was better than I’d expected but worse than I’d hoped.  Four eggs  out of seven pipped, two chicks hatched, and one survived.  Although it was emotionally tough, I chose to autopsy all of the dead eggs in hopes of improving my hatch rate for next time.

  • Chick dead in shellOne chick was speared by
    another’s claw as it tried to hatch.  The dead chick was hatching about half an hour later than its sibling and had just reached the stage where it was beginning to push the mostly detached egg top aside when its precocious sibling clambered over top of it and stuck its foot inside the crack.  In a way, this is a crazy fluke, but the experience also makes me think that it might be smart to have somewhere else for newly hatched chicks to fluff out rather than on top of their
    hatching siblings.  Since I’ve read that it’s best not to move chicks to the brooder until they’re fully fluffed out, that means a spare incubator or other enclosed, warm space.
  • Chick dead at pipping stageAnother chick started pipping, but only seemed able to push small chips out of its shell.  (I’ve enlarged the hole after death to see in.)  I don’t know whether
    the shell was abnormally hard or the chick was abnormally weak.  I’d read not to help chicks out of the shell, so I stood back, and the chick eventually perished (perhaps in part because an earlier hatched chick (not the same one as above) rolled the egg over so that the hole was face-down on the ground.)  Since the chick died anway, I wonder if
    I wouldn’t have been better off helping this obviously struggling chick?  On the other hand, it might have come out weak and had to be culled anyway.
  • Air pocket in dead eggThree eggs had nearly full-formed chicks inside but they didn’t manage (or, apparently, even try) to pip.  Some sources suggest that late stage dead in shell chicks are signs of incorrect humidity, often too high.  I didn’t keep track of the size of the air pocket over time by candling, but I may try that next time around to help me keep the humidity in the right range.
  • Finally, one chick hatched on day 22 but died less than a day later.  Chicks that hatch late and are “soft” are indications of the average incubation temperature being lower than optimal, and temperature was definitely the spot where I did the worst job during incubation.  Air temperature in the kitchen fluctuated between 45 degrees and 85 degrees and the incubator’s high and low temperature alarms went off several times.

The good news is that all of the eggs were viable and made it nearly to hatching time, which means our rooster and hens are all fertile.  And watching the first chick hatch was quite an experience — well worth the price of the incubator by itself!  Hopefully I can fix my mistakes and have more living chicks next time.


Incubation HandbookSince writing this post, I’ve experimented much more with incubation.  I developed a dichotomous key that makes it easy to figure out exactly what went wrong (and how to prevent the problem from reoccurring).  Learn more about troubleshooting the hatch in my ebook.

Permaculture Chicken: Incubation Handbook walks beginners through perfecting the incubating and hatching process so they can enjoy the exhilaration of the hatch without the angst of dead chicks. 92 full color photos bring incubation to life, while charts, diagrams, and tables provide the hard data you need to accomplish a hatch rate of 85% or more.

Float test of egg viability

Living egg floats at an angleRemember how you can tell if
an egg is too old to eat with a
float test?  You can use a similar test on day 23 or 24 with eggs that haven’t hatched to make sure the chicks inside are really dead.

The first step is to wait until most of your eggs have hatched.  I like to wait 24 hours after the last chick comes out of the shell, then take a close look at the remaining eggs to make sure none of them has pipped or been cracked.  (You don’t want to do a float test on a pipped egg or the chick will drown.)  This test is mildly traumatic to a chick inside an unpipped egg, so there’s no reason to risk it until you’re getting ready to toss the unhatched eggs.

A "yolker" floats vertically.Now fill a container with water that’s roughly baby bottle temperature — warm enough that you
can barely feel it when touched to the underside of your wrist.  (This is the same temperature water you use when proofing yeast for bread, about 100 degrees Fahrenheit.)  Wait until the water has stopped moving in the container, then take an egg out of the incubator and carefully lower it into the water with a spoon.

If your egg sinks to the bottom, it was probably infertile from the beginning and is definitely
a dud now.  If it floats, take a careful look at the floating pattern.

Does the big end stick up above the water with the narrow end pointing straight down?  Your egg is probably a “yolker” that either was a dud from the beginning or died young.

On the other hand, if your egg floats at more of an angle, almost horizontally, the chick might be alive inside.  (The chick is definitely still alive if the egg starts to move around on its own.)  Carefully take the egg out of the water, wipe it dry, and pop it back in the incubator for another day or two.

In the past, I’ve been guilty of pulling late hatchers out of the incubator prematurely, but with this float test in my arsenal, I suspect my hatch rate will continue to rise.