# Incubation Questions



## SulcataPardalis (Jan 27, 2012)

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.


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## Arizona Sulcata (Jan 27, 2012)

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!


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## ALDABRAMAN (Jan 27, 2012)

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?*


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## SulcataPardalis (Jan 28, 2012)

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


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## Tom (Jan 28, 2012)

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.


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## SulcataPardalis (Jan 28, 2012)

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.


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## cdmay (Jan 28, 2012)

Tom said:


> 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.
> ...



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


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## ALDABRAMAN (Jan 28, 2012)

Tom said:


> 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.
> ...


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## N2TORTS (Jan 28, 2012)

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~


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## ALDABRAMAN (Jan 28, 2012)

N2TORTS said:


> 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.*


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## cdmay (Jan 29, 2012)

N2TORTS said:


> 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.


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## Tim/Robin (Jan 29, 2012)

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.


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## N2TORTS (Jan 29, 2012)

ALDABRAMAN said:


> N2TORTS said:
> 
> 
> > 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?
> ...







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~


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## Neal (Feb 1, 2012)

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.


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## bettinge (Feb 1, 2012)

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.


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## bfmorris (Mar 7, 2012)

Tom said:


> 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?


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## bfmorris (Mar 9, 2012)

:crickets chirping:


Is this an unpopular topic?


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## Tom (Mar 9, 2012)

bfmorris said:


> Tom said:
> 
> 
> > I incubate at the same temps, so I think you are good there.
> ...



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.


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## N2TORTS (Mar 10, 2012)

bfmorris said:


> :crickets chirping:
> 
> 
> Is this an unpopular topic?



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


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## Tom (Mar 10, 2012)

N2TORTS said:


> bfmorris said:
> 
> 
> > :crickets chirping:
> ...



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


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## JoeImhof (Mar 10, 2012)

I would love to hear a clarification of this......

If you just take the eggs that start chalking (and therefore I assume are fertile for sure), should the hatch rate of those eggs, only those eggs, be near 100%? Or is there still a lower expected hatch rate of those?

thanks


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## Tom (Mar 10, 2012)

I don't know what I'm doing wrong, but I don't see chalking or much of anything on my eggs. When they get near term they get opaque when candled. Meaning they look like they are full of dirt or something and they are no longer translucent. Sometimes I get the orange glow vs. the yellow or clear, but even that is not 100% for me.

I just pull them out of the ground and put them all in the incubator and wait three months to see what I get...


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## Yvonne G (Mar 10, 2012)

I just wish I knew what temperature made females in the Manouria group. The only official paper I read said they should be cooler than most other tortoises. The first batch that hatched for me 15 or so years ago was incubated at 86F degrees. I still have 4 of those tortoises and they're male. Does that mean that if I up the temp to 88F degrees I'll get female? But that's not the "cool" that the experts tell you about. I have a 3 year old and a hatchling from about 88F but they're still too young to sex. And I'm wondering if I would have a better hatch rate if I cooled the incubator down to the 82/83F degrees ash shown in the paper I read. But at that temp would I for sure get males? I wish more were known about the Manouria. Its coming up on monsoon/nesting season for them and I'd like to do it right this time.


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## Tom (Mar 10, 2012)

emysemys said:


> I just wish I knew what temperature made females in the Manouria group. The only official paper I read said they should be cooler than most other tortoises. The first batch that hatched for me 15 or so years ago was incubated at 86F degrees. I still have 4 of those tortoises and they're male. Does that mean that if I up the temp to 88F degrees I'll get female? But that's not the "cool" that the experts tell you about. I have a 3 year old and a hatchling from about 88F but they're still too young to sex. And I'm wondering if I would have a better hatch rate if I cooled the incubator down to the 82/83F degrees ash shown in the paper I read. But at that temp would I for sure get males? I wish more were known about the Manouria. Its coming up on monsoon/nesting season for them and I'd like to do it right this time.



I've got a friend who breeds the blacks. I'm going to give him a call for you.

Left him a message. I'll let you know when I hear from him.


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## bfmorris (Mar 10, 2012)

Tom said:


> bfmorris said:
> 
> 
> > Tom said:
> ...



Very interesting, your summer eggs. In contrast, I have never and I mean never had a female lay eggs in the summer. Mine are very seasonal and always completely finished by the end of May.

Weirdly, I've seen a few split scutes at 84-85 f incubation, and I've seen split scutes in ground incubated specimens. Here, I know in-grounds incubate at much higher temps than artificial incubation because I have conducted temperature readings on ground temps at various depths down to eight feet, year around. Interestingly, at egg nest depths of about 24"- 30", the ground temperature here at ground hatching time (late August) is in the low to mid nineties f. All my temp readings taken with a certified thermistor.

After all this, I still tend to agree that higher temps are the cause of split scutes.

I breed rare Staurotypid turtles and I definitively know that higher incubation temps cause split scutes in them. However in sulcata I think there is more to learn yet regarding cause of the split scutes., and from the ground temps that I've been aware of for many years, there is still lots to learn there also.


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## Tom (Mar 10, 2012)

The summer egg thing is a new phenom for me. In prior years they only laid in winter. I think it is in part due to my warmer night house and the addition of Mazuri to their diet.

I would be very interested in hearing more about your in ground temps. My three foot deep underground boxes hover between 79 and 81 all summer long.

The steady, one temp, artificial incubation thing has always been perplexing to me. There must be quite a lot of variation even just from day to nit in an in ground nest... Love to hear more about your observations.


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## Yvonne G (Mar 10, 2012)

Stuart:

I hope you're not upset that we've more or less taken over your thread. If you'd like us to get back to your topic, just say the word.


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## ALDABRAMAN (Mar 10, 2012)

JoeImhof said:


> I would love to hear a clarification of this......
> 
> If you just take the eggs that start chalking (and therefore I assume are fertile for sure), should the hatch rate of those eggs, only those eggs, be near 100%? Or is there still a lower expected hatch rate of those?
> 
> thanks



*From my experience, I can visually see the "chalking" of our fertile eggs at about six weeks. This has been a solid indicator that they were fertile. The "orange glow " as Tom was indicating, I have seen this also and seems to be a solid indicator of fertility. I candle our eggs throughout the development process and can see the outline of the tortoise within the egg. I have not been able to photograph these events successfully, just can't seem to get the right light, etc. to work right.

Here is a good example of 100% fertile clutch of eggs, all have the chalking color, showed redish/orange color within, and i visually seen the mass inside. All twelve hatched out. *


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## bfmorris (Mar 10, 2012)

Tom said:


> The summer egg thing is a new phenom for me. In prior years they only laid in winter. I think it is in part due to my warmer night house and the addition of Mazuri to their diet.
> 
> I would be very interested in hearing more about your in ground temps. My three foot deep underground boxes hover between 79 and 81 all summer long.
> 
> The steady, one temp, artificial incubation thing has always been perplexing to me. There must be quite a lot of variation even just from day to nit in an in ground nest... Love to hear more about your observations.




Typically, I see summer clutches in those places animals are kept where it is too cold in winter for the animals to do anything at all outdoors which usually prevents summers from being to harsh, heat-wise. I mean frozen places like Oklahoma, where they spend the winter in indoor pens under spotlights, and lay eggs in mid-late summer after an outdoor period of mating and sunshine.

The nest level ground temps here don't vary that much from day time to night time during summer; they do gradually build until by late June it is quite warm then it stays warm, well into the fall although cooler, still in the mid eighties under there, in fall. Temps may drop a degree or three overnight in July-August, depending on if a summer rain occurs. The impossible to duplicate kind of heat from mass like that appears to do wonders for the animals.


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## bfmorris (Mar 12, 2012)

bfmorris said:


> The steady, one temp, artificial incubation thing has always been perplexing to me. There must be quite a lot of variation even just from day to nit in an in ground nest... Love to hear more about your observations.



I meant to reply to this and then promptly overlooked it. 

Yes, the earliest ground clutches do experience varying degrees of see-sawing temps, then less so to none as the season progresses and summer approaches. I'd temper this with the fact that unheated burrowed tortoises lay their eggs later in the year than artificially heated tortoises do, because they must wait for enough gain solely from the sun. So, the unheated animals bypass the egg-killing cold unless unusual weather strikes.

Anyway, what happens is, with ground clutches all ( I believe in captivity the very earliest eggs produced by artificially heated animals are killed, if left in the ground in AZ and So Cal) the eggs wait under there and all begin to develop at the same time once a threshold is reached. Then they all hatch & surface within just a few weeks of each other. So eggs put directly into the incubator I consider as eggs laid at that threshold. I do think day-night heat changes help eggs to breathe, though perhaps of less importance in an above ground incubation container.


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## SulcataPardalis (Mar 13, 2012)

emysemys said:


> Stuart:
> 
> I hope you're not upset that we've more or less taken over your thread. If you'd like us to get back to your topic, just say the word.



No, not at all. It's turned into a very informative thread.


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