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Humidity control by weights

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Sarah Meaders:
I am practicing with incubating my australorps in preparation for my future Ameraucana breeding. Is there anyone who maintains their humidity by weight, or has ever? I have read a few different "expert" figures, and I would like to hear experienced advice. Specifically, I have read that over the full 21 days, the eggs need to lose a total of 13% of their weight. The questions I have are how this is achieved, especially since day 18 is supposed to have increased humidity, limiting the weight loss for those final three days. So I have also read that the 13% needs to be lost by day 18, affecting the calculations. And finally, I have read several who stay with 12% over 18 days.

I may be splitting hairs here, but this is only my second batch in the incubator, and I am certain humidity and temperature control were issues in the first round. I would love to hear some veteran hatchers' thoughts and experience.

Thanks in advance!

Susan Mouw:

--- Quote from: Sarah Meaders on April 18, 2015, 09:28:03 PM ---I am practicing with incubating my australorps in preparation for my future Ameraucana breeding. Is there anyone who maintains their humidity by weight, or has ever? I have read a few different "expert" figures, and I would like to hear experienced advice. Specifically, I have read that over the full 21 days, the eggs need to lose a total of 13% of their weight. The questions I have are how this is achieved, especially since day 18 is supposed to have increased humidity, limiting the weight loss for those final three days. So I have also read that the 13% needs to be lost by day 18, affecting the calculations. And finally, I have read several who stay with 12% over 18 days.

I may be splitting hairs here, but this is only my second batch in the incubator, and I am certain humidity and temperature control were issues in the first round. I would love to hear some veteran hatchers' thoughts and experience.

Thanks in advance!

--- End quote ---

Hi Sarah

I don't bother with weighing to determine humidity levels and I'm hatching almost 100% for my EE/OEs. Not so high with my wheaten/blue wheaten Ameraucanas, but I have some older stock in there, so I'm not surprised. Too early to tell with the whites what my final hatch rate will be.

I keep it at 45%-50%, then bump it to 55%-60% for the last three days.

With the weighing and candling and all that we do with these eggs, I'm concerned that we might be doing more harm than good.

Sharon Yorks:
I usually keep my humidity at 32-39 during the first 18 days...start at 35 and you can fluctuate up or down, depending on the air cell. If there doesn't seem to be enough air cell, lower the humidity a little. When I go into lock down, I raise the humidity to anywhere between 63-68. My last three hatches have been 40 hatched chicks out of 58 eggs...30 chicks out of 50 eggs (but incubator shot up to over 101 during day 20 for a few hours)...and 35 chicks out of 48 eggs.

Having said that, I've recently noticed that it's not so much the percentage of overall eggs that are hatching as much as it seems that certain hen's eggs hatch out better than some others. I just noticed this pattern after my last hatch when I noticed that I set 5 eggs from one particular hen and none made it out of the shell, but all were fully developed chicks, then another hen's eggs (8) all hatched but 2 and another hen I set 9 of her eggs and all but 2 hatched. Then, looking back at the chicks I had previously hatched, it's always a similar pattern. It may be worth taking note of how many chicks you are getting from each hen.   

Don:
Sarah,  The moisture loss weight is very laborious and requires more delicate equipment than I have.  But I expect it would be a great way to calibrate an incubator hygrometer.  The references that I've seen indicate that it is 13% up until the time of pipping.  This can be 19-20 days so it is a difficult target when you are trying to be exact.  Moisture loss can be effected by the shell structure, thickness and some other factors.  So there may be differences in eggs from different hens as well as varieties and breeds.  So try to get an average of the weight loss in the whole clutch to see where your humidity needs to be.  You can use the air cell chart too but it is not as scientific.    Hatching is an art as much as science.  So try a number of things to get the perfect setting of Humidity and Temperature.  Thermometers can be and are often incorrect.  So start there with a calibrated unit or you may try to test against one that you can trust.  One method, make a slurry of ice water which should be 32 dg F to check the low end of a regular thermometer.  It should track to the high end.
   The other factors such as health/vitality and nutrition all play a part in the process.  So experiment as you go, suspect all variables until you get there.  Get the best results that you can, and make little changes after you get close to your goal.  Keep in mind that the ambient humidity changes as warm weather comes to your location.  Then make sure to document your steps to duplicate next year.   
    Some breeders swear that brooding with a hen for the first week is a magic bullet.  Some say that incubation on the side rather than small end down is perfect.  Everyone has their own secrets to the Art.  Be patient and Good Luck!       
       

Birdcrazy:
Susan, I agree with your quote "With the weighing and candling and all that we do with these eggs, I'm concerned that we might be doing more harm than good."

I seldom candle my eggs past 15 days. Every time you open the incubator you lose temperature but more importantly humidity. If you watch a hen setting on eggs, she may leave the nest quite often and sometimes for a lengthy time during the first week to ten days. From then on her times leaving the nest cut down and time off the nest decreases. The final 3 days she will not leave the nest even as the first chicks hatch. Much the same as we do on lockdown when transferring the eggs from the incubator to the hatcher. I used to open the hatcher and remove chicks as they hatched thinking they were dry and needed to get out and eat and drink. It finally dawned on me that shipping chicks through the mail, the chicks will ship well for 3 days without feed or water. After 4 days this becomes a critical issue. So I usually don't open my hatcher until the day after due hatch date to remove chicks. I will open it daily after that to remove the few stragglers. This way the humidity stays constant. I think you are right Susan sometimes we interfere too much with the incubation process. Just my thoughts.

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