Experimental Dehydrator Hatching - I'm doing it!

[Cornflower]

May 18th, 2023 I plunked 15 eggs into a dehydrator to see if they'll hatch.
I had commented on another post about this and I don't want to put my updates there. But there
are updates to tell!

Today is day 8, as of midnight May 26. Early this morning I candled some of them and saw... Oh man! I saw something
moving around! Two round shadows dancing and veins. The heart?

They're brown eggs so only the lightest and thinnest, 3 of the eggs, was I able to see into. Some of
these eggs have really thick shells and I don't know if I'll ever be able to see into them. But it was
exciting!

I got a free spreadsheet from a website and have been using that to track the weight loss. They are
1.2% underweight so far. I had traded a smaller bowl of water in on day 2 thinking that it was too
much humidity to use my really big cake pan. But seeing the loss of an 'nth of a gram I put the cake
pan back in. And I bought a digital temperature/humidity device and can see that the humidity is
now 21%. Pretty low.

The dehydrator is keeping a steady 97 deg F. I'm building a hatchery out of a large Styrofoam
cooler because the humidity wanted for hatching day is going to be about 70%.

My idea for doing this is because my old 1980's Excalibur dehydrator could fit four dozen eggs
or more. My friend is planning on doing large hatches, probably for broilers. I thought I could have
the pleasure of taking a bunch of that work off his hands. I don't think the dehydrator is going to
give us the hatch rate we want and that's not preferable if the eggs are valuable.

But the thing is working so far! A food dehydrator might be possible as a temporary back up incubator.
It has no heat mass, and holds the temp steady once you get it set. I didn't need to run it for 24 hours
before adding eggs, because once you turn it on it's instantly at temp. So if I had an incubator breakdown
I wouldn't hesitate to put eggs in there while waiting for the replacement to arrive.

PROS:
-This was cheap. I already had this, and old dehydrators can probably be picked up at garage sales.
-There was nothing else I really needed but a thermometer to dial in the heat, and pan for water.
-Comes to temperature immediately. Aside from your time adjusting the temp, the inside gets to temp
and holds very fast. No waiting for warm up.
-Would work as a temporary back up as long as you can get them into something better before Lockdown.


CONS:
-I don't recommend using it after lockdown.
-My pan barely keeps all the water in it for 48 hours.
-There isn't a way to refill the pan without opening the unit up.
-Lockdown needs 70% humidity and that's not going to happen in a sustainable way.
-I can't see into it very well, the drawer design doesn't give me a top down view.
-It's loud. I haven't enjoyed having that fan run constantly the past 8 days. I'm sure the chicks would be born with
tinnitus or deaf.
-It's making it hot in the house.
-Not what you'd use if you want a high hatch rate.
-Eggs are losing weight a tad faster than schedule.

 

[artbykarenehaley]

I wonder if running a refill line from outside to the water tray would eliminate the need to open the unit. You could hook up one of those drink dispenser jugs, then run the line into the dehydrator if it has big enough ventilation holes. I don't know if the dehydrator has a see through door though, if it doesn't you'd have to guess how long to hold open the dispenser nozzle.
When I have my styrofoam incubator running, I take a long pipette and stick it in one of the two vent holes to inject water into the incubator and I keep a sponge directly under that hole. I've considered setting up what I described so I wouldn't have to manually squeeze the water in over and over. Of course, I have been using a very tiny pipette since it's all I had. Just a thought about the dehydrator and the humidity issue

 

[Cornflower]

I wonder if running a refill line from outside to the water tray would eliminate the need to open the unit. You could hook up one of those drink dispenser jugs, then run the line into the dehydrator if it has big enough ventilation holes. I don't know if the dehydrator has a see through door though, if it doesn't you'd have to guess how long to hold open the dispenser nozzle.
When I have my styrofoam incubator running, I take a long pipette and stick it in one of the two vent holes to inject water into the incubator and I keep a sponge directly under that hole. I've considered setting up what I described so I wouldn't have to manually squeeze the water in over and over. Of course, I have been using a very tiny pipette since it's all I had. Just a thought about the dehydrator and the humidity issue

Thanks. Yes I can see through the front door but its heavily tinted. I can see the digital Acu mometer (we're still getting to know each other). I shine a flashlight in for better visibility, but I would like that top-down view when they hatch.
I do have some old aquarium tubing in various sizes. While there are no ventilation round holes, there is ventilation around the door. The door is set to have space around it. I'm thinking I will be able to squeeze a tube in and run it where I want it for filling water.
I also accidentally overfilled the pan and got water all over the bottom. It didn't leak so I kept going. It has brought the humidity up to 40% steady!
These eggs shells are massively thick so I can't see into but 3 of them with candling. I attribute their small weigh loss to their thick shell. I think with the thinner shelled varieties this clutch would not have so much hope.
I've been trying to build the other incubator and, there's so many problems to be worked out, it looks like we're going into lockdown in the dehydrator in four days.
I'm throwing in the towel - literally. I'm going to throw a towel into the water pan and thread it up over a tray above the eggs to make a swamp cooler and bring that humidity up to full, hopefully. With the thickness of these eggs I can make a few "dry" run attempts.
Thank you for your suggestion. I've wondered if I could get away with that. There's dozens of ways to do things but few will work and getting feedback helps me decide.

 

[Cornflower]

Update! 6/2/2023
Yesterday afternoon I went off the deep end and took a big chance altering the food dehydrator in an effort to increase humidity in there; I used patches of Duct Tape and covered the intake holes to the heater fan and watched over it for the rest of the day and night like a hen sitting on her eggs. <bad joke>

It took me all this time to get the courage to try it as this incubator... er... dehydrator is a family heirloom. But! It is heated with electricity running through a circlet of springs (a heating element), the fan is forcing air across the heating element, and the temperature is controlled by a bi-metallic spring thermostat. All these are inside the unit.

The chicks will be safe in there when they hatch
There is a wire mesh separating these components from the compartment where the eggs will be hatching. The hatched chicks will not be able to contact the fan or heating element. They also can't fall off the tray as it extends fully to all sides. They will have room to move also.

Why I thought this alteration was safe to try
This stuff is important to note. I can see that restricting the fan air intake isn't going to stop airflow circulating across the elements. The fan will now draw the already heated air from inside back through the heat element. The thermostat will turn the element off when it gets above the set temperature. I know this because the fan isn't being shut on and off, so it must be the heating element is turned on and off. If the temperature was being controlled by turning the fan on and off or low to high speed, then I would not have tried to close the air circulation. I don't think any dehydrator or incubator would work this way.

This means that's there's a really good chance nothing is going to melt in there if I close of those air intakes.

And it worked! The back of the dehydrator near the heater coil even felt a little less hot, meaning the element is working less.

And the humidity increased to 50% !!!

I think I've turned this dehydrator into a true incubator.

I was up all night into and watched the sun come up this morning, further pecking at it. The eggs got turned all night also, which is a plus.

Covering the heater fan air intake vent with tape was easy
I can control the amount of humidity by covering more and less of the holes, so I have used patches of tape instead of one large piece. According to the Digital Accu>Rite, the humidity and temps are really steady. I'm still keeping that pan full and it's emptying out more slowly I think. I would only use a heat resistant tape like Duct Tape or Electrical Tape here as this metal backside of the unit gets warm and is closest to the heating element.

Adding wet washcloths didn't work so well.
I also tried just covering the ventilating gaps around the front door but leaving the bottom gap open. I also added wet washcloths to the floor. For the next 8 hours I experience large fluctuations in temperature and humidity and couldn't get it to settle at that wonderful 95 F/50% humidity. I had to take those washcloths out and got it to 95F/ 40% RH and could drop into bed finally.

When I'm rested a bit more I plan to try raising the relative humidity (RH) to 70% by closing all the fan vents.

Circulating the heat back under the unit to heat water pan
Currently I also have removed the tape around the door and have just plunked a dry towel along the bottom of the door (outside) to encourage the exhausted heat to flow back under the unit and maybe warm that water tray up from below. I will be working with this concept some more also.

Being careful about temperature as I experiment with live eggs
As I fiddle, I am being careful not to allow large fluctuations in temperature to continue for long. The temps have plummeted to 93F and rocketed to 108F, so I definitely keep my eye on it when I make a change.

The dehydrator seems ok!
After 12 hours the unit isn't straining or overheating with the fan vents covered, I currently have only half of them uncovered and getting 40% humidity, but have had all of them covered and got 70% and more. I will have to do it over again without the washcloths to see if I even need them to increase the RH by that much for the lockdown.

Preparing for lockdown in a few days
I'm going to be buying some aquatic carbon filter medium to have on hand. This will absorb carbon dioxide and will be useful if the lockdown requires extreme ventilation restrictions. This will keep the oxygen ratio higher in there. I also already have tubed filtered air I can split off my daughters Mexican Salamander Axolotl fish tank. This will allow me pump a steady stream of fresh air into the incubator.

I'll also buy a mini bubble stone for the end of the that air tube, to have on hand. Bubbling the water pan could help increase humidity if the system is having trouble doing that.

Summary
So this is my update today and I am open to changing my mind about using a Food Dehydrator as an incubator - it might be a very good idea. Although using wet washcloths to increase the RH made it hard to keep both temp and RH stable (they wildly fluctuated and I was adjusting the temp dial for hours last night!), these are some of the same complaints I'm reading in the reviews of purchased incubators. I am wondering if high humidity can affect a bi-metallic spring? I'll be combing the internet for those answers as well.

Additional Con - I have food I've been wanting to dehydrate, and can't yet. I'm glad I hurried up and got my apples, celery and carrots done before putting the eggs in!

Supply list so far:
In use:
- Excalibur Food dehydrator 1980s 5-shelf square model, front loading
- Acu>Rite Humidity Monitor (model 00325/00326/00327)
- Rechargeable AA Battery for the Accu>Rite
- 14 inch cake pan (just fits the bottom of the unit)
- Duct Tape

Plan on using:
- Aquarium bulk carbon filter medium
- Aquarium filter medium bag
- Aquarium air hoses, small diameter (to run three separate hoses for adding water through a crack in the door, for running fresh breathable air into the system, for bubbling air into the water pan to increase RH)
- Small aquarium bubble stone
- Rubber dish mat (so the hatched chicks have good footing and prevent splayed legs. The plastic canvas dehydrator tray might be too slippery for them)

 

[Sally PB]

Following to see how it goes.

 

[Cornflower]

Update 6/4/2023
Candled early morning June 3
Out of 15 eggs
it appears four had never developed.
The other 11 appear to be alive and well.
Six displayed active movement. I'm so excited to see that!
The others have a very solid shadow up to the air sac.
Three I've I marked down in my records as "maybe I saw some movement".

In all of them I can see some vein structure and looking healthy. My eyes aren't so good, but I finally got a descent candle lamp constructed. They could still be hard to see into. These are thickly shelled brown eggs. Some are more lightly brown but only three of those lighter ones I was able to candle and trace the air sac by day 7. All air sacs are traced now as they were very easy to see at this stage. I've been going on faith with these eggs not being able to candle them very well and see how they're really doing. The other night candling was very rewarding.

The four that were not developed were elongated eggs. I had thought they were possibly going to be roosters, but they might have been not fertilized at all. They had a yolk-sized and shaped blob floating around. I imagine they've gone rotten, too. If I winged them at someone, it would stink 'n hurt <another bad joke>. I think I'll save them for the next election. <and crickets>

There's a gardening trick to bury eggs around your plants for nutrition. But who would bury expensive eggs just for fertilizer? Maybe the dud eggs from incubation are what's meant to be used?

High humidity DOES mess with the dehydrator's bimetallic thermostat
In my last update I said I would look for information about high humidity messing with thermostats. I'd had quite a fight for hours with my dehydrator when I added wet washcloths in an attempt to bump the RH to 70% just to see if I will be able to do this during hatching, and the temperature became impossible to maintain at 95F as it had been up to then. Temperature rose to 101F, then when I adjusted a nudge down it wouldn't drop, so I nudged it down more and more, and finally the temperature tanked out to 93F or even down to the high 80sF. It just wouldn't sit again at 95F.

Here's the article written by a manufacturer regarding the effects of high humidity on bimetallic switch thermostat. Here's the link but it's a pretty dry read <yuk yuk>: https://forum.digikey.com/t/disc-bimetallic-thermostats/680

In brief, it says high RH can cause electrical arcing across the spring. This may explain the wild fluctuation in temperature I experienced in a test run when raising the humidity to 70%, and the terrible struggle I had trying to readjust the thermostat all that day. I had to go back to 30% - 50% RH just to maintain a 95F temperature, then all was fine.

Arcing the spring for a long time could cause corrosion/oxidation or deformation then failure of the the metal (damage my humidifier!) It's a good thing I quit trying when I did.

The article suggests a "sealed" bimetallic spring (disc spring) would not have this problem.

Something to look for in an incubator would be a sealed bimetallic thermostat, if it uses a bimetallic. I've read reviews on some incubator models having wild temperature fluctuations and failure of the incubator after a couple uses, they broke. So if you are DIY building your own and buying a thermostat, or buying an incubator already built, ask how your thermostat is constructed. Ask for a sealed bimetallic if it uses a spring type thermostat.

Lockdown is 4am 6/5!
Moving on, early tomorrow morning around 4am I'll be locking the clutch down. I'm still not able to get a system that holds a steady 70% RH, but I got an idea.

Building a humidity controlled room inside the dehydrator
I spent all day today constructing an insert box that is air-tight, that I can pump humidified air into the box, then vent that air out more slowly keeping the high humidity around the eggs and away from the dehydrator thermostat.

If I succeed in creating the humid environment
I think I will need to slowly increase the humidity around the eggs over several hours to prevent sweating inside the eggshell into the air sacs. I don't want water puddling in there! And the temperature needs to stay steady through hatching and not fluctuate all through the process or it can cause condensation in pipping eggs. I'm being careful and conscientious.

18th day wrap up
The food dehydrator has worked very well to incubate all viable eggs to the 18th day.

I have looked at shopping for incubators, but I'm not encouraged to buy any because of some bad reviews. Uncontrollable temperatures were in the complaints, and sometimes the model breaks after a couple uses. These models may not have sealed bimetal thermostats. I experienced some of these results myself when I pushed the RH up to 70% adding wet washcloths. The problem might be unsealed bimetallic thermostat springs. Look for models that have sealed thermostat springs.

I see people with comparable conditions having different results, some good and some bad, and I've that the largest factor of successful hatch rates has to do with the quality of the eggs. I brought these eggs home from a farm myself, holding the crate up with my arm for the 15 minute drive to protect them from the jiggles and bumps in the cracked up roads. Eggs purchased through the mail might be having lower hatch rates from being jostled too hard in shipping. Even while I was being so careful, it was hard to protect the eggs from the rough roads.

All I could really do for these eggs in the dehydrator is use a large pan of water, for humidity. I've had to refill that daily. All my other experiments have failed. The RH has remained mostly at 33%, increasing to closer to 50% on humid days or at refill. Blocking the fan vents is ok to do and can be used to control RH. RH that is too high will break the dehydrator. It's really been easy and worry free; just refill the pan and add water to the floor, too.

Noteworthy, on humid days, it was much easier to keep the humidity inside the dehydrator at 50%. Lower humid days made it impossible to bump the dehydrator RH to 50% for longer than an hour when adding additional warm water to the floor of the unit.

Lockdown outlook
It could be that I may have to continue to accept the conditions of the dehydrator as is and allow the eggs to hatch at the lower RH. If my insert box can't be made to work, I still have the hoses I can trickle water through the door into the pan without opening the door while they're hatching.

Humidity and temperature do drop when opening the door. RH by about 15% and Temperature by about 20 degrees, but RH and temperature come back up quickly, within 2 minutes of closing the door again. But again, the humidity of the day has to be closely observed!

So if I really had to open the door it might be acceptable. The safety of doing so also depends on the atmospheric conditions outside.

BEST OF ALL!
In three or four days I may have 11 new baby chicks! I'm getting the brooder box ready!

More updates to follow! Thank you all for staying tuned!

 

[Cornflower]

June 5,2023 update and photos!
I think I got the inset box working! 12 hours later and the humidity seems to be holding at 74% for the last two hours closed and sealed. I feel like I can finally settle in for the final stretch.

Here's some photos of my Excalibur Food Dehydrator in use as an incubator. It's been through the jungle these past 18 days so please forgive it hasn't been given a wipe down lately. The duct tape was used for blocking the vents, but is now parked in case I find another use for it:

Above front view: You can see the two airlines going into the insert box. One is delivering plain air, and the other is not in use. It will be able to deliver humid air from the bubbler when turned on. The scale is holding the door closed. The airlines are too wide to close the door fully around them.

I spent the day yesterday drying out the bed of activated carbon that I had overwatered. The carbon is for absorbing carbon dioxide and providing a higher oxygen environment. There are airlines pumping air in, and a vent line near the bottom to let the heavier carbon dioxide air out. The inside of the box is still air, but the air pump is gently circulating new air in.

The insert box: Made of a precious pint jar box I use to store my canning jars. I've cut out three windows on the long end. I didn't cut the window all across for structural reasons. The inside is covered in plastic cling film glued down. The top is plastic cling film taped on. I added anchoring tape around the edge first, then added the film cover and taped that tape to the anchoring tape. This way I can pull the tape up to open it without ripping the cling film or the box.

It looks better in person. There is a patch of tape on that front top corner and the right window where the film tore. You can see the air lines are sealed in with tape, this also keeps the cling film from tearing.

The left window holds the Accu>Rite monitor. This is securely taped to the box, also using anchor tape in case I need to reposition it. I was carful not to cover any vents of the monitor because it might interfere with accuracy.
I can slide the tray out and examine the eggs from the top down and I have more time to visit this way without losing heat or RH inside the box. But if I open the cling film and slip my hand in to make adjustments the temperature in there drops quickly, and it takes a long time to come back up. This might also disturb the humidity as the temperature is rising again. So, only in emergencies should I reach in there now that the numbers seem to have settled.

View of the monitor through the cling film window
The strip of tape across the top you see here can be easily peeled up to allow access without ripping the box or the film liner because I created an anchoring tape along the edges of the box.

The tube under the monitor is only a few inches long. It's at the bottom of the box and it allows air out. This is forced out by the pressure of fresh air coming in through the supply tubes. Carbon dioxide is heavier air and sinks to the bottom, like water filling a glass. So the exhaust tube is near the bottom, with tape also to support the cling film it is punctured through.

Here is a top down view of the eggs in their final position

You can see the rubber drawer liner. I used two layers of that. Under this is a layer of lose activated carbon (aquarium bulk supply). I added water to that, just poured it over. It was too much (1/2 cup) so I had to dry it out some. Maybe a couple tablespoons would have been just right.

The bold text won't shut off, my apologies.

I used spare liner pieces to prop the eggs up on a little tilt, and on the sides so they don't roll around when the drawer is moved. I also taped that liner down around the inside so that new hatched chicks don't pull it up and get themselves stuck under it and tangled up.

Here is a close up of the airlines routing to the back of the eggs. Fresh air is coming out above the eggs to the back, and exhaust air is pushed out the front. The lines are cut a couple inches back from the rear wall so they are not getting blocked and securely taped into the corner so chicks can't get stuck behind the tubing.

Below: View of the eggs through the cling film window in the front:

Below: Closed up. It's harder to see through the tinted door. I'm using a basking lamp with a regular light bulb to shine in and check on things.

Truly a thing of beauty!

And for illustration sake, here is a view of the back of the dehydrator, those fan vents I've been writing about blocking to increase humidity:

I have some covered by tape to demonstrate. At times I had all those covered with tape. I could remove some tape to decrease the humidity. It didn't bother the dehydrator at all. The fan just recirculated the air that was in there. Only high humidity somewhere between 50% and 80% did the dehydrator have problems stabilizing temperature. I don't recommend pushing the RH over 50%.

And here's the bubbler bottle. It makes humid air. The long line from the air pump is going into the water with a bubble stone on it. This line has a check valve on it. This prevents water from siphoning back in to the air pump if the pump loses electric power (shuts off). This would ruin the air pump. The valve allows air to flow in only one direction. If the air, or any water tries to flow backwards, the rubber nipple closes. Some water can leak backwards if the pressure stabilizes, so it's a good idea to keep the air pump elevated above the level of the water.

The line without a valve isn't in the water in the jug. The end is above the water and the air in the jug is pushed through the line as the air bubbles up through the water. It's off right now, but it would be supplying the incubator with air that has some moisture in it. If I needed to add water to the charcoal substrate in the incubator, I can also pull this airline out of the jug and funnel a few tablespoons of water through it. That would land in the back corner behind the eggs. I can also heat the water in the jug for more humidity by sitting the jug in a pot of hot water, but not too hot. I don't want to risk scalding the nearby eggs at the other end!

Here were some photos I wanted to share to illustrate my post. I'll continue to update, because hopefully hatching comes next!

Thank you all for reading, commenting and reacting. It's been encouraging me to keep posting.

 

[Sally PB]

When is hatch day?

 

[Cornflower]

When is hatch day?

If they will hatch on the 21st from the beginning of incubation, it should be on the 8th of June at 4am. Can't wait!

 

[Sally PB]

Wow, that's this Sunday! Watching and waiting!