Informatiom required from experienced hatchers

[draag80]

Those problems are definitely associated with temp and humidity issues.  I think you're probably right about the bulbs going off and on - that temp may actually be dipping below what you think before heating back up.  Then the constant opening may cause the temp to drop for more time, too. 

Were they late hatching?

No the chicks that hatched, hatched right on time. But other eggs did not even budge. I candled them before discarding. All eggs seems to have developed but have died at various stages. Most of them were totally dark from inside likr they should be. But failed to hatch.

 

[draag80]

I have an old homemade incubator - the pics attached. No problems with bulbs going on and off. (I incubate still air, have not used the fan.) The thermostat resolution is 0.1 degree C which I think is a must. I have set the span to 1 degree C, so it turns the bulbs off at approx. 39.0 and turns on at approx. 38.0 The bulbs are 25W each. However, I put a medical thermometer on the top of the the eggs and adjust the thermostat according to reading of the medical thermometer. I hand turn and open the bator 3x times a day, sometimes it is open for half and hour... no problems ever, and I open the bator to take out chicks at hatchtime. However, if you use fan and live in a dry climate, it could be a problem. Humidity 30-35%, but I watch the air cells. Hatch rates are about 75-83%, which is not ideal, but I am happy with it.

83% hatch is a good percentage. I did not even get near that. I think its lack of turning that affected my hatch. I did not turn on day 2 for whole 24 hours. That could have affected it. You have a nice setup. Seems to be atleast 60 egg capacity. 80% means 50 chicks which is good.

 

[draag80]

1- lack of auto turner. Means I have to open the incubator slide the egg tray out and turn around 100 eggs which takes a good 10 mins. The eggs loose heat and humidity.

That by itself would not bother me. A broody hen will often stay off her nest for over an hour in warm weather when she takes her daily constitutional. Even in pretty cold weather she might be off 15 minutes at a time. Instantaneous heat or humidity in those ranges isn’t very important, it’s average heat and humidity (moisture loss) over the incubation period. The egg is pretty dense. It takes quite a while for the change in air temperature to affect the interior of the egg.

2- the fan turns on only with the heat and turns off with the heat which results in poor circulation.

This could be an issue, especially in a tall incubator with trays at different elevations. Warm air rises. When the fan’s off you may be getting quite a bit of temperature difference in the top and bottom of your incubator. In homemade incubators especially you can easily get some protected spots that may not be getting the full benefit of the air circulation. I’d certainly want the fan on at all times and take the temperature at different spots and elevations to assure the fan is doing its job and keeping the temperature constant throughout.

3- the thermostat has variation of 0.5 degree.

This may or may not be an issue. A lot will depend on where the thermostat is in relationship to the heating bulbs. If the thermostat is too far away, you may get quite a bit of heating or cooling in parts of the incubator before it kicks on or off, especially if that fan is not blowing. I can’t remember what the potential problems are if it is too close. I don’t know what the optimum distance is with yours but I suggest checking temps at different places to see how it’s doing.

Thanks for your views regarding the subject matter. I think you are very right about the fan issue. I drilled small wholes on side of all three incubators at egg level to cross check the temprature using a clinical thermometer by inserting its bulb inside the incubator. The clinician thermometer showed accurate results on the other two incubators , that is, exact 37.5 as their fans were continuously on. but this incubator showed 35 at egg level. I think lac of circulation is one of the problems.

Thanks for your valuable insight regarding the situation.

 

[draag80]

1 - Not really an issue but an auto turner would greatly help.  Studies have shown that the more frequently the eggs are turned the better they hatch.  Turning eggs is more important early in the incubating cycle than it is towards the end.  The old cabinet incubators were set to turn the trays every 3 hours.  The new cabinet incubators are set to turn the trays every hour.

2 - Critical error.  The fan has to be on all the time.  You can correct this by tapping into positive power line before the controller and bypassing the controller with the neutral return line or by providing it with its own power circuit.

3 - Not a serious issue and may improve once the fan is no longer controlled by thermostat.

Good luck.

You are absolutely right. Lack of turning and lack of circulation seems to be the culprit. Egg turning is seriously important

 

[draag80]

I never like to see a mercury style thermometer layed side ways. Have you tested a diffrent thermometer to ensure the temp is correct.

I calibrated the thermometer using warm water . Dipped both the thermometer in the pic and clinical in water and calibrated accordingly

 

[draag80]

After everyones valuable insight, i have decided to make the following changes.

1- make the fan direct so that it runs continiously.

2 - Install a digital controller.

3 - Replace 100 watt bulbs with 50 watt to avoid the sudden burst of heat.

4 - order two 36 egg auto egg trays which will fit right in. The capacity will decrease to 72 from 100 but i guess I will get more chicks out of 72.

Thanks everyone for helping me pin down the problem.

 

[Selga]

75-83% hatch rate - I meant hatch rate of fertile.

 

[draag80]

75-83% hatch rate - I meant hatch rate of fertile.

I would like to ask you how do you maintain temprature? Do u have a thermostat or a dimmer installed to control the heat of the bulbs?

 

[gpop1]

If I had to guess judging by the one picture you posted then I would say that you sterilized the eggs under the bulbs (104F internal will kill the egg).
4 bulbs is a lot of power for a small incubator like that. I also bet that when the door is open that all the bulbs are on constant while you hand turn the eggs which probably leaves some eggs cooking under the bulbs. I would suggest using diffused 25w light bulbs, It will take the incubator longer to recover after the door has been opened but it should reduce some of the hot spots especially once the fan is wired to run constantly.

Next batch mark each egg with a number then record the rough position inside the incubator. After hatch collect the un-hatched eggs that were not infertile and see if you have a pattern. Also record the air gap in at least 2 eggs and compare it to a online chart to see if you have a humidity problem during incubation.

 

[draag80]

If I had to guess judging by the one picture you posted then I would say that you sterilized the eggs under the bulbs (104F internal will kill the egg).
  4 bulbs is a lot of power for a small incubator like that. I also bet that when the door is open that all the bulbs are on constant while you hand turn the eggs which probably leaves some eggs cooking under the bulbs. I would suggest using diffused 25w light bulbs, It will take the incubator longer to recover after the door has been opened but it should reduce some of the hot spots especially once the fan is wired to run constantly.

Next batch mark each egg with a number then record the rough position inside the incubator. After hatch collect the un-hatched eggs that were not infertile and see if you have a pattern. Also record the air gap in at least 2 eggs and compare it to a online chart to see if you have a humidity problem during incubation.

Very useful information indeed. You are right about the bulbs. The power is too high. Also when i open for turning, it remains constantly on. The eggs under the tray get cooked. Absolutely right. That's what I call good insight.

It also proves by the fact that a few eggs that hatched were from the side close to the door. Meaning the eggs inside got to much heart. Next time i am gonna install 25 watt bulbs and turn the fan constantly running.

I think now is clear what the problem was.