Incubating 101

[Tbrad]

Either way works fine. If you are hand turning them, it's generally a good idea to put marks on the egg so you can see that it has been turned the right amount. Put an X on one side and an O on the other. Or use red and black ink.


Enough development occurs that some people can see it by candling by the third day. But how much you can actually see will depend on how dark the room is you are in, the color and shade of the eggshells, and the quality of your candling equipment. The experience of the person candling also plays a part.

In lighter eggs I can often see quite a bit of detail later in incubation. In some of my darker green eggs I'm just looking for blobs and air cell, no real detail.


Turning the eggs accomplishes different things. It helps keep the yolk and embryo centered so it does not touch the inside of the shell where it could get stuck. It helps body parts form in the right place. It helps with the development of certain fluids in the egg as it develops. After two weeks a membrane has formed around the embryo that protects it from contact with the inside of the shell. Body parts are formed. There is no longer a need for turning for those fluids. With chicken eggs you can stop turning them after 14 days without a problem. Continued turning does not hurt them but it is not necessary.

We typically go into lockdown after 18 days of incubation. This is where we increase the humidity, position them for hatch, and stop turning. You could stop turning earlier but it is convenient to do this at the same time, especially if you have an automatic turner. That's why most people say 18 days.


There have been a lot of studies on the effects of turning the eggs, during storage as well as after incubation starts. These are typically using automatic turners and involve a large number of eggs so they have more data points. These studies are typically paid for by the commercial operations that may be hatching 1,000,000 chicks a week in one of their hatcheries and they have several different hatcheries scattered around. A small percentage difference will be noticeable to them but not necessarily to us. What might be better for them might be irrelevant to us. That happens on a lot of these studies for different things. It's "better" so we think it has to be done or it's a guaranteed disaster. That's often not the case for us.

Turning three times a day works well for me. It doesn't hurt to turn more often, it's "better" but the incremental gain is not worth it to me.

If you hand turn it is recommended to turn an odd number of times. The goal is that they spend a roughly equal amount of time in each position. If you have an odd number of turnings it works out that they spend every other night on the same side. If it is an even number of times they don't.


No, we don't have to. A slight decrease doesn't hurt.

This comes from two different places. In the commercial industry their problem in those huge hatchers is that the embryos are producing a lot of heat and with 60,000 eggs in a hatcher the eggs in the middle can cook from that self-generated heat. Their problem is to keep the eggs in the middle cool enough while keeping the eggs on the outside warm enough. They do this with fans and by manipulating the heat. We don't have this problem with our small incubators. It doesn't hurt to drop the temperature a slight amount, with the heat the individual embryos are generating they are not going to run into any problems as long as you don't get ridiculous.

The other place where this comes in is that warm air rises. A lot of us use still air incubators. You can have a difference in temperature depending on where the egg is in the incubator vertically. If you have a forced air (has a fan) the temperature should be the same everywhere in it. But with a still air the elevation matters. When you go into lockdown, especially with an automatic turner, you often put the eggs back in at a lower elevation than they were incubated. How much lower temperature depends on how much the elevation changes. You do not want to drop the temperature in a still air. In a forced air it won't matter that much unless you get ridiculous.


Be careful when transporting the eggs. You don't want to shake them up or subject them to really hot or cold temperatures. That's why people warn you about shipped eggs. One time I transported 30 eggs on the floorboard of my car over a rough country road. Only 10 hatched. I should have had them cushioned and on a seat.

Start all the eggs in an incubator at the same time. You don't want a staggered hatch. Way too stressful and often not successful.

The reason lockdown is set for 18 days is that the 21 day thing is just a target. It is not unusual for eggs to hatch a full two days early or late for various reasons. One big reason is the average incubating temperature. If the temperature is a bit warm they can hatch early, cool and they can be late. But there are other factors too like heredity, humidity, and how and how long they are stored before incubation begins. Once an egg pips it is possible you can shrink-wrap a chick. That's where that membrane that develops around the chick dries out and shrink, trapping it so it cannot hatch. That's why we increase humidity when we go into lockdown. If you open the incubator after a chick has pipped you release the humidity and you can cause shrink-wrap. This doesn't happen that often. Some people open the incubator during lockdown without issues. If I have an emergency I will too. But I have caused shrink-wrap so I know it can happen. Since some eggs can hatch early, if we lock down after 18 days or development they are already in lockdown when these early ones pip.

Count the days right. An egg does not have a day's worth of development the moment you put it in the incubator. It takes 24 hours for it to have a day's worth. So you say "one" the day after you set it. You may be surprised at how often this mistake is made. It usually doesn't matter with the hatch if you lock down a day early, the uncertainty in when they actually hatch is so great and you have that much flexibility in many of these things, but it can cause a lot of stress if you think they should be hatching and they are not. A good way to check your counting is that the day of the week they are put into the incubator is the day of the week the 21 days is up. If you set them on a Friday the 21 days is up on a Friday.

Wow! Thank you so much!!!

Really the only question I have now is when you say to position them for hatching, what position is that?

 

[FC16]

Wow! Thank you so much!!!

Really the only question I have now is when you say to position them for hatching, what position is that?

I think it depends on how you’ve incubated them (laying down or standing upright), if they were laying down when positioning them for hatch you’d take out any turners or stuff like that, and space them out around the incubator - they’ll roll around anyway but I still do it. Some people also put a material/mat in the incubator for hatching to prevent legs getting stuck or other issues like that.
I’m not sure about upright hatching as I haven’t done it before but I’m sure it’s a similar prep

 

[Tbrad]

I think it depends on how you’ve incubated them (laying down or standing upright), if they were laying down when positioning them for hatch you’d take out any turners or stuff like that, and space them out around the incubator - they’ll roll around anyway but I still do it. Some people also put a material/mat in the incubator for hatching to prevent legs getting stuck or other issues like that.
I’m not sure about upright hatching as I haven’t done it before but I’m sure it’s a similar prep

This is one of the setups I currently have. The other 3 are polystyrene, glass aquarium and plastic tote with microfiber blanket as an insulator but they all have the same internal setup. I was told the eggs needed to be elevated and I have it surrounded by a mixture of sand, vermiculite and perlite to help insulate as well. I also added several plastic Tupperware with sponges to aid the humidity levels.

I am worried about when they hatch and falling out and was considering removing the cardboard box that is elevating the eggs. I was told it would help with air circulation but it doesn't seem necessary.

Anywho, if you have any additional tips, that would be great, otherwise wish us luck!

 

[FC16]

This is one of the setups I currently have. The other 3 are polystyrene, glass aquarium and plastic tote with microfiber blanket as an insulator but they all have the same internal setup. I was told the eggs needed to be elevated and I have it surrounded by a mixture of sand, vermiculite and perlite to help insulate as well. I also added several plastic Tupperware with sponges to aid the humidity levels.

I am worried about when they hatch and falling out and was considering removing the cardboard box that is elevating the eggs. I was told it would help with air circulation but it doesn't seem necessary.

Anywho, if you have any additional tips, that would be great, otherwise wish us luck!

I’ve never tried a homemade incubator so not too sure, but that looks very cool. What humidity is it going to be for the first 18 days?

 

[Ridgerunner]

Really the only question I have now is when you say to position them for hatching, what position is that?

As always you have options. And it will depend some on which incubator you have. There are a lot of different commercial models. Some may not give you options.

One method is to lay the eggs flat. It doesn't matter if they were incubated laying flat or on end. I incubate in an auto turner standing up and lay them flat for hatch.

Some people like to hatch with the eggs standing up with pointy side down. I don't do that so I'm not great on the details. In a lot of photos I see they use styrofoam or cardboard egg cartons and cut away some of the material to give better air flow around the egg and to maybe make it easier for the chick to pip. I don't know how necessary cutting that away really is. When the first chicks hatch they crawl all over and play rugby with the unhatched eggs. I don't see that as a probem but some people do so they do this to keep the eggs stationary.

I did not realize you were building homemade incubators. If you have a mentor with experience do what they say. I've never built one so I will not comment. Good luck!

 

[Tbrad]

I’ve never tried a homemade incubator so not too sure, but that looks very cool. What humidity is it going to be for the first 18 days?

That's where we are struggling. I've read 50-60% so my goal is 55%. Then I've read in other forums people keeping it at 45%.

We are also struggling with the readings bc I'm not 100% all were accurate. We ran these for 48 hours making the necessary tweaks to get the temp between 99.5 and 100 using a thermostat and the sponges in water and at this point are just crossing our fingers.

I also read after all this that they need ventilation holes but then my humidity struggles so idk

 

[FC16]

That's where we are struggling. I've read 50-60% so my goal is 55%. Then I've read in other forums people keeping it at 45%.

We are also struggling with the readings bc I'm not 100% all were accurate. We ran these for 48 hours making the necessary tweaks to get the temp between 99.5 and 100 using a thermostat and the sponges in water and at this point are just crossing our fingers.

I also read after all this that they need ventilation holes but then my humidity struggles so idk

Yeah humidity is very hard to get just right, I like to aim between 30-40% as I’ve always found 50 too high when hatching but everyone is different. I think they do need ventilation holes (but then again I’ve only ever used incubators I’ve bought so I’ve never properly studied it), there are lots of ways to gain/lose humidity. In an incubator that was cheap and bad I used, it struggled to gain humidity, so I used bottle caps filled with water and put them on the tray with the eggs. This worked really well and each time I turned the eggs I’d just add a little water to each cap. If it’s too high you can take a cap out, or if it’s too low you can add another in. I’m sure there’s other methods out there too, if you search humidity in the search bar.
I also recommend getting a few hygrometers so you can have an ‘average humidity/temp’ in the incubator and makes a more accurate reading.

 

[Tbrad]

Yeah humidity is very hard to get just right, I like to aim between 30-40% as I’ve always found 50 too high when hatching but everyone is different. I think they do need ventilation holes (but then again I’ve only ever used incubators I’ve bought so I’ve never properly studied it), there are lots of ways to gain/lose humidity. In an incubator that was cheap and bad I used, it struggled to gain humidity, so I used bottle caps filled with water and put them on the tray with the eggs. This worked really well and each time I turned the eggs I’d just add a little water to each cap. If it’s too high you can take a cap out, or if it’s too low you can add another in. I’m sure there’s other methods out there too, if you search humidity in the search bar.
I also recommend getting a few hygrometers so you can have an ‘average humidity/temp’ in the incubator and makes a more accurate reading.

I will aim for a lower humidity then. We have funnels built in as a means to try and add water without opening and it's plugged with a paper towels so I can use that as a ventilation hole and go from there.

I do have others I'm using to compare but I'm noticing that it depends on placement. It's a forced air incubator so I'm a little confused as to why

 

[FC16]

I will aim for a lower humidity then. We have funnels built in as a means to try and add water without opening and it's plugged with a paper towels so I can use that as a ventilation hole and go from there.

I do have others I'm using to compare but I'm noticing that it depends on placement. It's a forced air incubator so I'm a little confused as to why

Yeah I’d just try not to stress about it, you can use guides such as this to see if the humidity is where it should be at, and what effect it’s having on the egg

I also never worry too much about opening the incubator from day 1-18 as I always think about sometimes a hen will be off the nest for hour or so and the eggs always do fine

 

[Ridgerunner]

As I said I've never built a homemade incubator so I'll stay away from "how to" but talk more about "what" you need to accomplish, if that makes any sense.

The embryos and chicks are living animals that breathe oxygen. The egg shells are porous so they can exchange bad air (CO2) for good air (Oxygen). During the early stages of incubation they aren't that developed and don't really need much oxygen. Pretty much they don't need it at the start, but the closer they get to hatch the more they need oxygen. Vent holes are hard on humidity but later in incubation and at hatch they are important. With a forced air incubator just a small vent hole should be OK, it doesn't take a lot.

Never trust the instruments you use unless they are calibrated. This means thermometers and hygrometers. You need to use a better quality thermometer than this, but the next time you are at a hardware or big box store that sells thermometers that measure outside air temperature, look at the readings on thermometers on the same shelf and see how different the readings are. I've seen 9 degrees Fahrenheit difference. The higher quality thermometers we should be using may be better than that but they can still have quite a range. Some are adjustable so you can calibrate them. Hygrometers are the same, they aren't all set perfectly. A forced air incubator is supposed to have the same humidity throughout but especially with a homemade incubator it is possible you can have pockets with different humidities. That might explain why you get different readings in different areas but my guess is that the hygrometers are not calibrated.

The way you control humidity in the incubator you are building is by wet surface area. The depth of the water in the reservoirs doesn't matter to humidity, just how fast it runs dry. How much wet area is available for water to evaporate from? So to increase wet surface area you either add more reservoirs or use a sponge or cloth to wick water out of the reservoir to wet the sponge or cloth. This does not react real fast, you have to be patient to see what the results are. When I spill water when filling the reservoirs and get an area that is supposed to be dry wet, humidity spikes until that water evaporates and the area becomes dry.

There is no perfect humidity for every incubation. Different humidities work differently for different people. Some people do better in the low 30's, others do better in the 50's. There are a lot of different reasons for that. Some of that is how the incubator is built. That's more than just the difference in forced air or still air. Height above sea level makes a difference due to air pressure. The temperature and moisture level of the air going into the incubator makes a difference so it may be seasonal. The big commercial operations find that if they move an incubator from one spot to another in the incubating room they may need to tweak humidity settings. That one surprised me but a poultry science professor that consults with the big operations mentioned that in a talk one time.

The good news is that there is a relatively wide range of humidity settings that give good results. You don't have to be that precise but you need to be in that window that works best for you. My general suggestion is to choose a humidity and try to be as consistent as you can during the incubation. Then tweak it based on your results. That's one of the reasons some of the incubators you buy say to run a test hatch with cheap eggs the first time before you risk expensive eggs. With your science project I'm not sure you have that luxury. For your science project you'll need to keep notes. Humidity is one thing I'd chart.