Breeder Chronicles: Incubator Issues

This has been one of the hardest months that I’ve had as a breeder. I was very excited about having clutches laid early in the season and having 5 in the incubator at one time. Unfortunately I had two eggs hatch very late, after 45 days, and found two very weak geckos with their yolk sacs still attached. Neither hatchling  made it past a week. To make matters worse all the eggs in the incubator with the exception of one went sunken and moldy.


The Problem

I’ve been trying to figure out why I had the mass egg loss all at the same time and why the eggs that did hatch progressed so slowly. I had made the egg cups exactly as I did the previous year using the GEO’s. I was using the same incubator and I followed my typical setup that I outlined in an earlier article. So I decided to check the temperature fluctuations inside the incubator by placing a digital thermometer in there that will save the highest and lowest temperature that it encounters. I was surprised to find out that over 24 hours there was a 6 degree difference between the highest and lowest temperatures. It went from 82.4 to 88.2 degrees.

Possible Solutions

I’m not really sure why this would happen since the incubator can both cool and heat which I thought would make it stable almost any place that I put it. Based on what I found out in the temperature test I don’t think that I can really rely on this incubator anymore. I have moved it back where I had it last year, in my kitchen at the center of my house. Right now it’s been between my rack and my Tortoise tub that has a huge mercury vapor bulb on it. Maybe that was part of the problem but I’m not convinced.

It think that the lesson to be learned is twofold. One is that there are no guarantees when working with animals and nature. It’s possible that this is all just a coincidence and I got really unlucky. I tend to think that 8 or so eggs going bad at the same time and having the only two hatchlings suffer from the same issues be a little too coincidental. The second thing is that when it comes to incubation there is no substitute for a quality thermostat.

I know one thing for sure. If I was using a quality proportional thermostat I wouldn’t even be questioning my temps. On/off style thermostats are more than sufficient for racks because a change of a couple of degrees certainly isn’t going to kill your geckos but temperature fluctuations certainly can have very adverse effects on incubation. A proportional thermostat will be a more stable platform because instead of bringing the temperature up and then allowing to fall a certain amount before powering it up again it will increase or decrease the power being used to hold the temperature steady.

So in addition to moving my current incubator to its new location I’m going to build a new incubator using  wood or an old mini fridge and a proportional thermostat. It will give me peace of mind and one less thing to worry about. I’d also like to make a second one so that I can have both male and female temps going at once. Hopefully I can change my luck and I won’t lose any more eggs this year.

What do you think?

Written by Justin Hansen

Justin Hansen's first reptile, an African Fat Tailed Gecko, sparked an interest that ended up consuming a dorm room in New York City and almost getting him expelled. Now that he has the space he is renewing his passion for breeding geckos. Currently focusing on Leopard Geckos he hopes to be able to branch out to other gecko species. He will be found at once he has a spare moment to finish the site.


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  1. Great article!

    I am also having a very hard time maintaining temperatures with my incubator. Especially since summer is almost here and the temperatures can be very high. What I always do is when I find the temperature to high, I will open the top of the incubator to let fresh air flow come through and decrease the temperature a little bit. It sounds like you have a different incubator then I do though. I have the Hova Bator Incubator 1602N Still Air. Good luck!

  2. Justin,
    Sorry for your loss. I know this can be discouraging. But instead, you share your experience for the better of the hobby. This is what it is all about.
    There are so many factors that can come into play. Temp variance certainly can contribute like you wrote. As well, confirm that that your feeding and supplementation schedule is consistent with last year and matches the animal’s requirements.
    Hope you figure this out and please keep us posted. Thank you for taking the time to record this info.

  3. I appreciate the condolences. I do believe that it could have something to do with my supplement schedule. I have switched to once a month instead of every week since I put calcium without D3 in the tubs this year. I’m going to go back to supplementing once per week.

    I’m also hoping that moving the incubator to a more stable temp area will help. Even though it will cool if the room is too hot the incubator doesn’t switch gears until the temp is at least 3 degrees in the wrong direction. That is exactly what I believe is causing the large 6 to 8 degree temp swings.

  4. I am sorry to hear about your difficulties. Hopefully you will find the right answers and be successful next time. Thank you for sharing your story with us.

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