Incubation Questions

[SulcataPardalis]

I am realtively new to breeding tortoises. I have been keeping them for over 15 years, but it has only been the last 18 months that I have had success in breeding them.

The following is my setup

This is my incubator - I know the temp is reading low, but I have just opened the door to check and air the eggs.

I use vermiculite and place each clutch laid in a plastic box with holes drilled in the top. I make the vermiculite so that it holds water, but isn't dripping wet.

However, I seem to be getting only about 60% hatch rate. As you can see from this photo, two eggs appear infertile (orange ish) and one is starting to go mouldy.

Which is a real shame, as they all appear to 'chalk' after laying.

What am I doing wrong? I simply make a depression in the vermiculite and place the egg in it. Should I be burrying them further?

Temps are kept at 31/32 degrees.

Any advice would be very much appreciated for next season eggs.

Thanks for looking.

 

[Arizona Sulcata]

Looks like you're doing things right. The hatch rate for myself is usually similar. In most cases just like in any other animal, fertilization is usually around 45% so at 60% you're doing great!

 

[ALDABRAMAN]

Sounds like things are good, hatch rates are determined by fertility, not egg volume. I also eventually check every egg for fertility after the incubation period is well over, if all fertile hatched, 100% hatch rate.

How do you control the temps in your incubator?

 

[SulcataPardalis]

I have a habstat pulse thermometer controlling a ceramic heater. Works very well with stable temps throughout the incubator.

 

[Tom]

I see a few things that I would do differently. These things will have nothing to do with whether or not your eggs are fertile, but they may have something to do with hatch rates.
1. Don't do your water to vermiculite ratio by "feel". Weigh both. I have found a 1 : 1 ratio to work the best for me for sulcatas and leopards. I tried a little wetter and popped a few eggs. I tried a little drier and a couple babies had some trouble getting out of their egg shells. They still made it, but it was noteworthy.
2. Drill your vent holes on the sides of your she boxes, instead of the tops, and only drill around 4. You will lose less moisture this way, and its still plenty of ventilation. Using this method I only sprinkle a small amount of water into my shoe boxes once or twice during the entire three month incubation, and then I add a bit of water when I see the first pip. I find that a little more moisture helps them escape from their eggs a little easier.
3. I place my eggs around 2/3-3/4 into the vermiculite. No idea if this matters or not, but I prefer it.

I incubate at the same temps, so I think you are good there. One thing to consider is the time of year that the eggs are produced, fertilized and laid. I have lower fertility on clutches that are produced during hot weather. I have higher fertility on clutches that are produced during colder weather, during the winter months. My fertility rate varies a lot throughout the year. As low as 20-30 % for summer eggs, as high as 80-90% for winter eggs. I have only had two clutches with 100% fertility and both of those were laid toward the end of winter. I have heard similar stories form other keepers. My male sulcata breeds (or attempts to breed) nearly every day, btw.

 

[SulcataPardalis]

Thank you for the advice. I will modify my boxes with side holes and be a little more accurate with the measuring of the water to vermiculite ratio.

My leopards seem to start laying at the end of September, with the latest eggs laid on new years eve.

Being relatively new to breeding, is the fertility issue due to the male, or female.

 

[cdmay]

I see a few things that I would do differently. These things will have nothing to do with whether or not your eggs are fertile, but they may have something to do with hatch rates.
1. Don't do your water to vermiculite ratio by "feel". Weigh both. I have found a 1 : 1 ratio to work the best for me for sulcatas and leopards. I tried a little wetter and popped a few eggs. I tried a little drier and a couple babies had some trouble getting out of their egg shells. They still made it, but it was noteworthy.
2. Drill your vent holes on the sides of your she boxes, instead of the tops, and only drill around 4. You will lose less moisture this way, and its still plenty of ventilation. Using this method I only sprinkle a small amount of water into my shoe boxes once or twice during the entire three month incubation, and then I add a bit of water when I see the first pip. I find that a little more moisture helps them escape from their eggs a little easier.
3. I place my eggs around 2/3-3/4 into the vermiculite. No idea if this matters or not, but I prefer it.

I incubate at the same temps, so I think you are good there. One thing to consider is the time of year that the eggs are produced, fertilized and laid. I have lower fertility on clutches that are produced during hot weather. I have higher fertility on clutches that are produced during colder weather, during the winter months. My fertility rate varies a lot throughout the year. As low as 20-30 % for summer eggs, as high as 80-90% for winter eggs. I have only had two clutches with 100% fertility and both of those were laid toward the end of winter. I have heard similar stories form other keepers. My male sulcata breeds (or attempts to breed) nearly every day, btw.

This is some really good advice that I will try myself. Never too late to learn something.

 

[ALDABRAMAN]

I see a few things that I would do differently. These things will have nothing to do with whether or not your eggs are fertile, but they may have something to do with hatch rates.
1. Don't do your water to vermiculite ratio by "feel". Weigh both. I have found a 1 : 1 ratio to work the best for me for sulcatas and leopards. I tried a little wetter and popped a few eggs. I tried a little drier and a couple babies had some trouble getting out of their egg shells. They still made it, but it was noteworthy.
2. Drill your vent holes on the sides of your she boxes, instead of the tops, and only drill around 4. You will lose less moisture this way, and its still plenty of ventilation. Using this method I only sprinkle a small amount of water into my shoe boxes once or twice during the entire three month incubation, and then I add a bit of water when I see the first pip. I find that a little more moisture helps them escape from their eggs a little easier.
3. I place my eggs around 2/3-3/4 into the vermiculite. No idea if this matters or not, but I prefer it.






I incubate at the same temps, so I think you are good there. One thing to consider is the time of year that the eggs are produced, fertilized and laid. I have lower fertility on clutches that are produced during hot weather. I have higher fertility on clutches that are produced during colder weather, during the winter months. My fertility rate varies a lot throughout the year. As low as 20-30 % for summer eggs, as high as 80-90% for winter eggs. I have only had two clutches with 100% fertility and both of those were laid toward the end of winter. I have heard similar stories form other keepers. My male sulcata breeds (or attempts to breed) nearly every day, btw.

 

[N2TORTS]

Great thread ....now I have a question for you all ...What about the "light" that your eggs are exposed to during incubation? Does anyone have any input on this?
One would figure in the wild the eggs would be underground and hence virtually no sunlight and or incadescent light source. I myself have similar set ups as we all chat about , but I block most if any light source during incubation.

JD~

 

[ALDABRAMAN]

Great thread ....now I have a question for you all ...What about the "light" that your eggs are exposed to during incubation? Does anyone have any input on this?
One would figure in the wild the eggs would be underground and hence virtually no sunlight and or incadescent light source. I myself have similar set ups as we all chat about , but I block most if any light source during incubation.

JD~

I keep all my incubators in a large closet/room that is almost always dark, no lights on.

 

[cdmay]

Great thread ....now I have a question for you all ...What about the "light" that your eggs are exposed to during incubation? Does anyone have any input on this?
One would figure in the wild the eggs would be underground and hence virtually no sunlight and or incadescent light source. I myself have similar set ups as we all chat about , but I block most if any light source during incubation.

JD~

My incubators are kept in a fairly dark location. The room will get interior lighting from time to time but the incubator keeps the eggs shaded.

 

[Tim/Robin]

I made all of my incubators. The have two 25 W red "party" bulbs inside. These are connected to a proportional thermostat that dims them as needed. To my knowledge the light has not hindered the hatching of any eggs. I tried using heat tape but was not happy with the result. I may tinker a bit more but what I am doing now seems to work. Sometimes the old saying "if it ain't broke, don't fix it" stands its ground.

 

[N2TORTS]

Great thread ....now I have a question for you all ...What about the "light" that your eggs are exposed to during incubation? Does anyone have any input on this?
One would figure in the wild the eggs would be underground and hence virtually no sunlight and or incadescent light source. I myself have similar set ups as we all chat about , but I block most if any light source during incubation.

JD~

I keep all my incubators in a large closet/room that is almost always dark, no lights on.

---

My incubators are kept in a fairly dark location. The room will get interior lighting from time to time but the incubator keeps the eggs shaded.
[/quote]

Good deal Carl .. I was hoping you and Greg would pip in~ It's interesting to see all the different home-made and elaborate setups , but within alot of these I view ... I see too' much light with glass doors ect ...for incubating tort eggs~

 

[Neal]

60% hatch rate is pretty good I would say, but this is coming from someone who's hatch rate experience is in the teens. Judging from the pictures of your hatchlings in your other thread, your adults have South African Leopard genetics, and as such, your eggs might benefit from a cool down period to break diapause.

Something to consider.

 

[bettinge]

Great Thread! I love that huge home made incubator.

I had a 59% hatch rate this summer compared to a 78% last summer. I attributed the decline to the horible May 2011 in NY. It was wet and cold, and not optimal for tortoises outside.

 

[bfmorris]

I incubate at the same temps, so I think you are good there.

Just curious if you see split scutes at the 88-89 f temps you indicated you're incubating?

One thing to consider is the time of year that the eggs are produced, fertilized and laid. I have lower fertility on clutches that are produced during hot weather. I have higher fertility on clutches that are produced during colder weather, during the winter months. My fertility rate varies a lot throughout the year. As low as 20-30 % for summer eggs, as high as 80-90% for winter eggs. I have only had two clutches with 100% fertility and both of those were laid toward the end of winter. I have heard similar stories form other keepers. My male sulcata breeds (or attempts to breed) nearly every day, btw.

Have you formulated any theory on the cold/hot weather fertility variations?
Would this report be on sulcata eggs? Are you saying your sulcata produce eggs in summer?

 

[bfmorris]

:crickets chirping:


Is this an unpopular topic?

 

[Tom]

I incubate at the same temps, so I think you are good there.

Just curious if you see split scutes at the 88-89 f temps you indicated you're incubating?

One thing to consider is the time of year that the eggs are produced, fertilized and laid. I have lower fertility on clutches that are produced during hot weather. I have higher fertility on clutches that are produced during colder weather, during the winter months. My fertility rate varies a lot throughout the year. As low as 20-30 % for summer eggs, as high as 80-90% for winter eggs. I have only had two clutches with 100% fertility and both of those were laid toward the end of winter. I have heard similar stories form other keepers. My male sulcata breeds (or attempts to breed) nearly every day, btw.

Have you formulated any theory on the cold/hot weather fertility variations?
Would this report be on sulcata eggs? Are you saying your sulcata produce eggs in summer?

I do not see any split scutes at those temps. Fife told me that typically you will not see split scutes until you start getting above 90. Remember that he funded and supplied eggs for a professional level lab study on this...

In the hottest parts of summer with consecutive days of 110+ and nights that don't cool much, my reptile room can creep into the low 90's. Not a problem for the torts or inverts. I just shut off the lights and heating stuff. In the past I would move any eggs out of the reptile room and into my garage, where it never gets above the low 80s, for summertime incubation. This last summer I left them in the reptile room, but moved them to the concrete floor. Out of roughly 6 summer incubated clutches, one clutch had one split scute, and another clutch had three. So I saw a total of four split scutes this summer. These were my first ever. I won't be incubating in the reptile room any more over summer. Interestingly, "The Crying Tortoise" book says that 8-15% split scutes is normal for wild clutches... My Gpp breeder friend who incubates in the ground also sees around 10% split scutes on his in ground incubated leopards.

And yes sir, I am only reporting about my sulcatas, and yes sir, mine breed and produce eggs in summer now too. They pretty much lay all year long now. I get a clutch per female about every 6-8 weeks. Occasionally one will stretch it to 12 weeks in between.

 

[N2TORTS]

:crickets chirping:


Is this an unpopular topic?

I belive Tom just made you eat your crickets!.....

 

[Tom]

:crickets chirping:


Is this an unpopular topic?

I belive Tom just made you eat your crickets!.....

Haha. No no. I just missed his question until late last night...