Bad hatch rate: incubating in the summer heat? Or humidity is wrong?

[suburbanfarm]

Help please, I've lost about a third of the chicks that went into lockdown. I know it's summer here so I can consider whether some loss is related to that. But I want to check whether I'm doing anything wrong.

The air cells looked great prior to lockdown. I just did a quick candle around day 23 to see if anyone was stuck, and I was quite shocked at the size of the air cells.

This was my first time doing dry incubation for the first 18 days, because previously I struggled to keep it below 50% humidity. So humidity was around 30% for the first 18 days.

Then I bumped it up to about 65-75%.

Was that too high? In previous hatches I thought some of the chicks looked like they were getting stuck so I thought humidity may have been low.
Or is it temperature related?

Any advice please, I have been reading so much and it feels awful when they develop and don't make it.

 

[suburbanfarm]

Just to clarify, around 2/3 hatched already. Of those not hatched, there may still be a couple alive so I've left them in.

 

[spartacus_63]

30% would be very low in my incubator. I typically run 45%-50% 1-18 and 55%-65% from lock down to hatch. I doubt that the lock down humidity would cause 1/3 to not hatch. Once they get to lock down, most issues that cause lock down failure were caused by developmental issues, IMHO. Did the chicks pip?

I weigh my eggs; when they are laid, at Day 7, 11, 15 & 18 to see how they are progressing. The goal is to have a weight loss of around 11%-13% by hatch day. This allows me to adjust the RH as I go along.

 

[suburbanfarm]

Thanks for your reply.

Only one had pipped. So if I didn't stuff up the humidity in lockdown then it could just be the perils of incubating in summer?

Last couple of times I tried to keep it 45-50% I was constantly trying to adjust it because it went too high. I couldn't keep it below 50 with one channel in the Janoel 24.

If 30-35% is too low then I could try creating a divider so I have a half size water channel?

I can get some pictures of air cells when I call it over today.

 

[Mellowmalt]

I've read about dry incubation, have been advised it is best but I stick to an even humidity of 50%.
I think there is far more to it than dry incubating or not. Personally I feel like if the incubator hasn't got many eggs in it the humidity needs to be higher, if the incubator is full of eggs they release enough moisture that humidity overall can be a bit lower.

I also treat smaller eggs as needing higher humidity because they have a larger surface area in relation to the egg mass inside of it..

I have also wondered if the room humidity is relevant, I find if I match the humidity in my incubator with the humidity in my room the eggs seem to be in the right range.

The most important thing to me is to check the size of the air cell to determine if humidity has been running too high or too low.

I also completely agree with spartacus that too often humdity is considered the cause for problems when it is well known that temperture is critical to development, humidity is not. Humidity just needs to not be too low or too high - thats it. 30% is too low imo.

 

[suburbanfarm]

I've been keeping the temperature at 37.5 and I have extra thermometers etc, but I have another thermometer coming that I will calibrate my current thermometers to make sure they're reading right.

Rooms here are around 30-40% I think currently

 

[spartacus_63]

I have also wondered if the room humidity is relevant, I find if I match the humidity in my incubator with the humidity in my room the eggs seem to be in the right range.

I run a room humidifier in my incubator room constantly and try to keep the humidity above 40%. That is about all I can hope for here in the winter. I do believe it makes a difference and keeps the incubator more stable on the humidity. I also have a heater that keeps the incubator room at a more constant temperature overnight when the rest of the house cools off.

 

[suburbanfarm]

The air cells looked right like the charts I'd been looking at. Whereas previous hatches trying to aim for 45-50% it kept going over. Room humidity is quite high here at the moment.

What else might I be doing wrong? Temperature? I will calibrate my thermometers when my calibrated one arrives

 

[jher77]

Room humidity isn't going to be the same humdity in the incubator. You need to know the humidity in the incubator.

If you take the same air and heat it up, the relative humidty is different. Looking at the chart, say your room temp is 70 F and RH is 75% the dew point is 61. Now find dew point of 61 at 100 F, the relative humidity is ~28%.

The rooms humidity and temperature does play a role in the incubators humidity because that is what is being pulled into the incubator through the vent. That is why some people can "dry incubate" and some can not. If your rooms RH is fluctuating badly then the incubators RH will fluctuate too such as with an air conditioner.

If you want to really know what humidity to run in your incubator, then weighing the eggs is the key. You can get a gram scale at walmart or harbor fright.

 

[JaeG]

Where these your eggs or did you buy them? If you bought them were they shipped? Shipping can adversely affect the hatchability of the eggs even those that make it to lockdown.

The age of the birds can also affect the hatchability of the eggs. I just hatched some of our pullet's eggs and 2 out of the 5 didn't make it. They were fine at lockdown, but there's quite a process for the chick to transition to breathing for itself and some just don't make it. My other girls are much older, between 5-7 years of age and I ended up with 14 chicks out of 21 eggs set (3 of them weren't fertile).

I dry incubated because my eggs were all very fresh. If the eggs were older and had already started to lose moisture I would have raised the humidity to around 35%.

Definitely calibrate your thermometer as temperature is the critical component. Slightly too low and the eggs struggle to lose sufficient moisture.

Your lockdown humidity was fine in my opinion.