Egg incubation in the
Australian Bearded Dragon
Below are excerpts on egg incubation in bearded dragons (BD or beardies) from the Pogona list, an internet discussion list dedicated to the topic of bearded dragons (Pogona vitticeps). You will find some redundancy, and I have slightly edited some posts to make them fit this context. I chose entries to give a variety of views and information, rather than to recall everyone's opinion encyclopedically. I like having all these different voices and opinions. The variety of opinions helps emhasize that there is often no single correct way to proceed.
In the photo below, kindly supplied by Tammy Belicic ("Tammy & the zoo"), two eggs are resting on a bed of vermiculite in an incubator, and one baby has begun to hatch. The edge of the container can be seen at the bottom..
Kathryn on setting up the Hovabator
I use a Hovabator, because I have not had good luck with home-made devices. I put water in the channels on the bottom, as in the general instructions (putting the water in just the channels has been sufficient in my "circulated model", which has a fan; filling the areas suggested for the "thermal" model, which lacks a fan, should suffice for that model), and then use little sandwich-sized containers with damp vermiculite for the eggs themselves. I put the containers on the screen. I also bought a combined thermometer- humidistat unit to measure both temperature and humidity inside. The thermometer that comes with the Hovabator seems quite useless. The combined unit cost less than $10 at my local Meyers (a discount store in Michigan)
Kathryn, on calibrating a Hovabator
The following instructions will help you home in on the right temperature range quickly, so you only have to do relatively fine adjustments:
When you first calibrating the incubator, check the room temperature. Then, adjust the little device on top of the Hovabator (or whatever turn screw on whatever brand--the Hovabator are the ones I know). The arrows on top tell you which direction to turn to increase temperature, or decrease temperature, and there is a little light on top indicating whether the heat is on or not.
If you plug the incubator in, and the light comes on, then twist just until the light goes off. You are now in the range of temperatures around the room temperature (Lets say room temperature is ca 75 degrees; if so, then what you want is somewhat warmer. Twist the control just a little in the "more heat" direction, until the light comes on again. Come back 15 minutes later, check the inside incubator temperature (use a better thermometer then the one that comes with the incubator), and adjust accordingly.
If you plug the incubator in, and the light (the one indicating the heat is on) does NOT come on, then twist just until the little light does go on. Come back 15 minutes later, check the inside incubator temperature (use a better thermometer then the one that comes with the incubator), and adjust accordingly.
Bill Mears on the needed steps
- Buy incubator
- Get vermiculite and make it moist enough to form a ball when squeezed (test by making a ball and throwing it at your neighbors cat)
- Fill base of incubator with moist vermiculite and lightly tamp it down -I use the base of a yogurt tub
- Put lid on incubator and fiddle around with thermostat until a probe lying on the surface of the vermiculite gives you a reading of 81F-84F (lower is OK, hotter is not). This takes a week and a lot of cussing sometimes! Make sure you have it in a COOL place so it can't overheat on a hot day.
- Shout - "lay NOW" at your dragon
- Place eggs in small thumb depressions in the vermiculite and brush the vermiculite around them (eggs with veins on top). The first time you do this, you will space them out all nice and neat and run out of room when clutch #3 is laid. The next year you'll cram them in to save space.
- Sit back and wait 70 days or so and consult endless lists of baby names for all the potential babies.
- Oh yes- find a really good source for crickets; you're going to need to buy them by the 1000.
JillyRN regarding humidity
I have been told that the humidity should be as high as 70-80%, but they will still hatch at even lower percentages. My first clutch hatched in 56 days with humidity around 50% using a homemade incubator. I had a hard time getting the humidity any higher than that. Currently, I am incubating 2 more clutches and have been unable to keep the humidity higher than about 40-50%... I mist them every other day to add extra humidity, but still am unable to raise it much. These are incubating in a "Hovabator". All the eggs look fine at 40-50% humidity and the first group should be hatching in about 7-8 days. 85% humidity in the incubator seems a little on the high side. If the temperature is about 84 degrees and humidity 85%, and the eggs are still collapsing, than I would say that the eggs are probably infertile. Too much humidity can make the eggs absorb too much water and mold, too high temperature will "cook" the eggs and too low temperature will prolong hatching. I hope this helps.
Kathryn on incubation:
Mix the vermiculite and water in a ratio of about 5:1 by volume (i.e. 5 cups vermiculite to 1 cup water) or 2:1 by weight, before introducing the eggs; better to do so even before the eggs are laid to let the vermiculite reach the correct temperature. The vermiculite should be damp but not soggy. It should just hold its shape if you squeeze it in your hand, and shouldn't then drip water.
I use a Hovabator with a fan--I've had very poor luck with other devices, such as jury-rigged aquaria, although some people seem more adept at such things than I am. Note that any incubator will only heat the eggs; it won't cool the eggs, and if the room temperature gets high, your eggs can cook. In addition, the incubation temperature will vary with room temperature (and lid opening, etc.); some variation is natural. However, given the variation, I keep the incubator temperature at 81 degrees; it can go up to 84 without damage to the eggs. In my experience, even brief periods at higher temperatures have been lethal, although I've heard some anecdotal reports of successful incubation at higher temps (e.g., below). I tend to the more conservative approach. In addition, to keep the eggs within the desired range in the hot Michigan summers, I keep the Hovabator in the only air-conditioned room in the house. After all, I do have my priorities.
If you look closely at the eggs, the fertile eggs will have a round spot, about 1 centimeter (ca 3/8 inch) wide, usually visible through the shell, where the embryo lies. The spot will look like a more translucent portion. In the next couple of days, you may see blood vessels developing in that region. Then you will see a red spot (an oval area right under the shell) is the embryo and its associated membranes, which have lots of blood vessels running through them already. If you have difficulty seeing the spot, darken the room and use a pen-light (this is called "candling" the egg, since the candle predates flashlight, as do eggs...). Turn the penlight on and put its bulb end right up against one end of the egg (i.e., the somewhat more rounded end, or even the somewhat more pointy end) and rotate the egg until you see the spot.
This spot indicating the embryo should be place UP in the incubator. If you are placing it down, it would explain early lethality. Eggs can be fertile without showing an obvious spot--if the embryo is just a bit younger when laid, the spot will look oval but translucent or clear, with maybe a short red streak down the middle of the long axis of the oval. The red streak is the embryo; the rest is translucent because the blood vessels are just beginning to grow out from the embryo. Candling can help you see these features more easily, although often you can see them without candling.
The eggs do take up water as they develop. A healthy egg looks plump when laid, rather than dented or partially collapsed. A few dented eggs are often seen in first matings, and are not a sign of trouble. Some eggs will not have an embryo in themthese often look dented, or will soon become so (and often grow mold) or remain dented in the incubator. Remove them. I put all hatched eggs in the incubator, embryo side up when I can see it by candling, and remove those that remain or become dented after a few days; always remove the eggs that are yellow and smelly or moldy. Note that as hatching nears, eggs will begin to dent. Don't throw these away. This denting is a sign of incipient hatching.
My eggs have generally hatched between 65 and 76 days of incubation at 81 degrees F, although they can take longer. A cooler period before you begin incubating--or even a relatively cool interlude during incubation--doesn't hurt them (don't, of course, refrigerate them....), but even brief periods at too warm a tissue are potentially lethal.
Incubator medium: vermiculite
Nathan Tenny on Perlite and vermiculite
Vermiculite has been questioned but, well, Perlite has its hazards too. It's very hydrophilic; we occasionally get Pacific tree frogs on the patio who have gotten into a flowerpot and ended up with bits of Perlite "glued" to them. They have to be soaked to clean them up; pulling the Perlite away would tear the skin dreadfully, I think. Sand? I think that's the kind of danger level we're talking about with vermiculite. Sand is a hazard; hard-rock miners used to commonly, and occasionally still do, go down with an ailment called silicosis, which is basically the effect of inhaling too much fine particulate silica. For that reason, if you buy a jar of lab-quality silica sand, it often has lurid warnings about the dangers of inhalation. But nobody worries about going to the beach or playing in a sandbox---the risk from that amount of exposure is *waaaaaay* down in the noise.
Everything, after all, is potentially harmful in one way or another...
BTW, I found the materials safety data sheet for vermiculite, basically a gummint-mandated braindump on the contents, properties, and dangers of the stuff: http://www.schundler.com/msdsverm.htm. The press coverage already posted would seem to indicate that asbestos is not associated with vermiculite intrinsically, but with a particular mine where it was a by-product; the actual effects of inhaled vermiculite seem to be pretty minimal. ("Nuisance dust" is the technical term. Perlite is classified as one, too.)
Ronnie Buck on water content in the vermiculite
I think the higher moisture content does effect the hatching time because the water has a cooling effect. The air temp is currently 82.4° in the incubator, but the temps under 1" of wet vermiculite is 78.2°. I also cover the eggs completely with vermiculite for several reasons. 1) it keeps the eggs from drying out on the top side 2) I feel it may help to keep any mold off of the eggs as they are completely covered 3) it keeps light from reaching the eggs, which as Kathryn has noted, can cause a startle reflex and tear the yolk stem resulting in the death of the embryo. This is probably a larger factor with candeling the eggs as the sudden intense light would be what startles them, but I have a home made incubator with a bright light in it so I can see (I use a black light for heat on a thermostat) and I don't want to risk it.
Deborah on using sand instead of vermiculite
Add some warm water to the dry sand, that is what I do for mine. I add just enough to make it stick, then mound it in a pile at one end of a container with a hole started. Mine did not like the vermilite, or any combo of it with sand. Good luck.
Steve Grenard on time
A ninety day incubation period is not unusual either. After a breakdown of an incubator, a breeder friend near me incubated a clutch of vitticeps eggs for 5 months at room temperature (around mid 70s on avg) and all but one hatched.
Randal Gray on time
As an interesting note, when I use to breed dragons and chucks, I put all the eggs in the same incubator with my Uromastyx (about 88-89F). It worked for all the species.
Pete on dangers of high temperatures
I would be careful using elevated temps. I am on three herp lists and there is always a lot of talk about eggs. This is my opinion only so FWIW: I believe that elevated temps cause an increase in respiration inside the egg. If you increase respiration too much, you exceed the shells capability to transfer gases quickly enough and the embryo smothers. Now maybe chameleon eggs are more sensitive to this but I have seen stories of eggs going full term and babies stillborn, but perfectly formed. Even tho it takes longer, I will opt for lower temps. Also, there has been some discussion on this list not too long ago about high incubation temps causing weak hatchlings. This is just my opinion YMMV
Kathryn on time and temperatures
The gestation time is variable, depending on temperature and other factors. Often the eggs from the same clutch hatch over the period of a week. Pam Hanratty said that Lucy's first clutch (incubated at 82 degrees F) hatched in 82-89 days, while her second clutch (incubated at 84 degrees F) hatched in 68 days. Pete's have hatched in 54 days at 84 degs. Mine usually take about 63 days at 84 degrees. Steve Grenard reported that some incubated by a friend of his at room temperature hatched at five months.
Damien on success rate
Well, in the wild, they don't get a 100% hatch rate. Very far from it. Probably more like a 30% or less. Some clutches remain unhatched completely. There isn't a very high success rate in the wild. In captivity, we want as many as possible to hatch don't we? Thats the main reason for incubation I'd say.
Sarah in Nebraska on hatching times
I incubated at a constant 81-82 degrees, occasionally misting with distilled water
The eggs were laid on March 11th
9 hatched between May 9-14
6 hatched between May 16-22
Thea on clutches per year and temperature
Our female produced 5 clutches last year, the first in March and the last in October. The average size was around 18 eggs. We incubate at 83 -84 F and the average incubation time was 55 to 60 days. She produced 85 babies in total last year. She started early this year and produced her first clutch on Jan. 30th and the second on March 1st.
Ivan Davis on high temperature causing deficits
I actually have had some experience with raising the temp towards the end of the incubation cycle with Water Dragon Eggs and have indeed noticed that batches where this was done do hatch faster at the cost of hatchling health.. Or so it seemed, never could consider my research in this area very
scientific, just a semi-formal observation.
Ronnie Buck, records
If eggs are white and firm, they are good. Mine are running about 75 to 83 days for hatching incubating between 82 and 83°. Ongoing records for the 2001 Hatch are available at http://groups.yahoo.com/group/pogona/database. Last year, my most unusual pattern was with Breeze. She laid 5 clutches averaging 21 eggs per clutch with the first three clutches 3 weeks apart to the day, then she took a 3 month break and produced the last 2 clutches (she was only mated once at the beginning of the year) 19 days apart. The year before (her first season) she had a very similar pattern also with 5 clutches but she was mated after she laid her first 3. I think she averaged 17 eggs per clutch IIRC.
Kathryn, about egg wrinkling:
It could be:
- Low humidity in the incubator. Humidity should be between 70-90%. Buy one of the cheap "humidistats" at a hardware store. I got one with a temperature gauge for around $12 at a discount store. If the shriveling is due to low humidity, adding water NOW can save the eggs.
- Eggs were infertile, or the embryos failed to develop, due to birth defects, inbreeding, or mere youth of the parents. High temperatures can cause lethality, even when very transient--one reason I incubate at 81 degrees, rather than the more common 84 degrees. It gives me some latitude. Also, remember that if the room temperature raises above 84 degrees, so will the incubator--it has no cooling circuits. The only room in my house with an air conditioner is the room I where I put the Hovabator. BDS first!!
- Eggs get a little dent in them and may appear to be collapsing just a day or two before hatching.
Todd Kuhlinayn on never give up on a "bad" egg
Well, I got a good lesson today on exactly why we FREEZE eggs rather than throw them in the trash. It also goes to show just how bad an egg can be and still have a chance.
There was a plastic container in the back with about a dozen eggs in it. It seemed to me that they were supposed to be Hingeback Torts. It had gotten quite dry to the point that a couple of the eggs were completely dried out and I KNEW these were bad. Anyways, I went thru and got the substrate moist again and re-placed the eggs. There were 2 of them that were pretty bad, 3 that were questionable and the rest looked good. The 2 bad ones I set on the counter while I was getting the others setup.
When I finished I decided to cut the eggs open to see if they had developed at all. Surprise Surprise, out pops a nice yellow yolk and a very baby BEARDIE. Not much movement but he was definitely alive. The other one was worse (both eggs were extremely sunken in and about 1/3rd the size of the good ones) so I cut it open too. Another live baby beardie. I put them both down but it still amazes me that they were alive based on the condition of those eggs.
Moral to the story? Never give up until the others have all finished hatching:-) Get the eggs rehydrated and hope for the best:-)
Ronnie Buck on moving eggs later
Yep, it's no trouble relocating eggs. I've transferred eggs to another tray several times in the past and as long as you don't drop them, roll them, or "slosh" the yolks around, it's no trouble. The eggs will feel firmer in a week, which will help settle your nerves. They really are pretty tough and you would have to have to pretty much 'hurt' them on purpose (unless dropped) to cause any harm. I'm really not even sure about rolling the eggs. I had one of my igs get into my incubator last year and dump one of my egg trays onto the floor 24" below the incubator. The tray landed upside down and the eggs scattered everywhere. I found one 6 feet away under my bed. A few of the eggs were crushed, and one was missing all together (I assume the ig ate it) but the remaining eggs looked perfect. I lost my data in my pc from that time frame, but IIRC the eggs were like 45 days or so into incubation and every one of the remaining eggs hatched at 56 or 57 days.
I got a frantic phone call from a previous list member one night. He and his brother were wrestling in the house and his brother kicked the Hovabator, which flipped it over and scattered the eggs as well. Three of the eggs collapsed with a few days, but the remaining clutch hatched some 30 days later.
I think there are certain times during development that rolling an egg could kill the baby inside. I don't know if perhaps the yolk stem gets torn or what, but I bet Kathryn could give us a whole list of possibilities.
Kathryn and Ronnie
One possible preventative is the powder used to treat athlete foot fungus. I used it one year, but think it is best not to put it directly on eggs, as it can impede the gas exchange through the shell if laid on heavily, as any fine powder would do. Also, some chemicals can be taken up through the shell and the anti-fungicides are fairly toxic if taken internally. When I do use it, I spread some on the bottom of the plastic container, and put in clean damp vermiculite, and then the eggs in little depressions. Another thing--don't use the convenient "spray" version of the powder directly on eggs. It comes out very very cold, and immediately kills the embryo (voice of sad experience).
In my experience, healthy eggs don't grow mold. I've had dead eggs, covered with mold, touching healthy eggs that do fine. It is best to just dispose of an egg that has mold on it, and increase the air circulation and perhaps change the vermiculite, if mold is growing anywhere in the incubator. Others have found that eggs will hatch, even with fungus.
The eggs that went moldy while incubating two years ago were either non-fertile, died during incubation, or were laid by Lucy in her cage, rather than in the laying box. Here's my half-baked theory..... Ordinarily, I used new Schultz's vermiculite, which had been moistened with boiling water and allowed to cool. The egg-laying box itself was disinfected prior to adding the vermiculite. Lucy only remained in the box long enough to lay her eggs and bury them, then she was returned to her cage. Consequently, the number of mold spores to which the eggs were exposed was relatively low. I always handled the eggs with new disposable latex exam gloves, and I incubated them in fresh vermiculite which had also been pre-moistened with boiling water. The eggs were placed in sterilized rubbermaid food storage boxes, which had about 5-7 small holes drilled into the lids.
I had very few eggs become moldy when using this technique. The one time I did have significant problems with mold, Lucy laid her eggs earlier than expected, and laid them in the substrate in her cage. I attribute the molding to the fact that the substrate was not sterile, and the eggs were probably contaminated to a significant extent when they were laid. It also didn't help that Bruce walked all over them! These eggs were also fertile (as indicated by initial pink color and presence of blood spots), but became moldy within a week or less. I was really disappointed....
Sterility isn't really an issue---the eggs aren't sterile, the room the incubator sits in isn't sterile, so trying to start with a sterile substrate and keep the mold out that way is kind of like trying to drain the Mediterranean with a spoon.
It's a little nerve-wracking, but some people have been successful keeping molds and fungi at bay with various topical antifungals (athlete's-foot powder and the like). It's not clear whether that's 100% safe for the eggs, but then the mold isn't 100% safe for the eggs either.
You don't *have* to have an incubator with a fan, by the way. The fan helps with air circulation, but the standard fanless Hovabator clearly allows enough air circulation for BD eggs to thrive---plenty of people have hatched out plenty of eggs that way, remember.
In my experience, healthy eggs don't grow mold. I've had dead eggs, covered with mold, touching healthy eggs that do fine. It is best to just dispose of an egg that has mold on it, increase the air circulation and perhaps change the vermiculite if mold is growing anywhere in the incubator.
Where do they get the air?
Bill Mears A question:- after Dulcie had laid the eggs, they were covered and the hole tamped down really hard- very hard and I had to be really careful digging them up. Assuming this is a repeat of what happens in the wild, the hatchlings must be pretty darned strong to get out- especially if the climate changes and the soil firms up even more. What does all of you think? Which leads to.....if they are laid underground and packed in tight, why do we leave them uncovered in the top of an incubator? Wouldn't they have a more stable temperature if they were covered- even by loose vermiculite? Anyone tried that method?
Todd Any ideas where the "fresh air" would come from when Mom buries them in the dirt? :-) For me I simply made depressions that allowed the eggs to sit at a depth of about 1/3-1/2 the egg. I would not toss out any until they are obviously dead (sunken in, extreme discoloration, hard) as the indication of the fungus does not in itself mean they are bad. You do want to control it though as I mention above. I check on my eggs once a week. If you pull them out to candle them, be sure to be VERY gentle and not rotate the egg. Once the embryo has started to develop, it must be placed back as it was taken out or the chances of killing the egg are quite good.
Kathryn Darned if I know. Seems like the way my females pack them down, that they would be lucky to dig out at all. I'd bet that one element of the generally immense lethality BDs experience would be due to inability to dig out; that eventuality is probably balanced by the certainty of some predator sniffing them out and eating them if they were laid nearer the surface. Sounds like a good subject for a field study--follow a female BD around, see where she lays her eggs, set up a little camera and check their fate.... In regard to our standard method of incubating eggs half-exposed, the only thing I can say that seems halfway reasonable is that--it seems to work (as long as you dont candle them when development is advanced. They have developed a "startle response" and can actually damage their exterior blood vessels and die. Some of us lightly cover the eggs near the end). And given that it is working I feel awkward in changing it. It may be that, in trying for 100% hatch rates, we are doing things that simply wouldn't work in the wild. E.g., we can optimize the humidity without drowning the eggs by placing them ON but not buried IN damp vermiculite. Our solution wouldn't have worked in the wild, since any wandering predator would scarf up a half-exposed egg, but we have the nice incubator cover to take care of that problem (Bill's marauding cat aside). We can separate the eggs so that if one goes bad, its decay doesn't infect an egg that is touching it, and moreover we can see it is bad and remove it. We can supply good air circulation, so the embryo doesn't suffocate in the egg, and so fungus doesn't get an advantage. We can candle them and put them embryo-side up, to further increase the embryos chances. Our selection is a lot kinder than the natural kind...
Beardie Mom (aka) Janet on hatching
Got a nose stickin out of an egg. Watched it. It is actually amazing. The egg shakes a little, then it wobbles end to end, and then a little crack....and then it gets bigger and the egg wiggles around a little more...wa-la then we have a nose!
Dan DSLIZARDS on hatchlings
Once we feel that the eggs are near hatchout time, Sue and I remove the lids from the vermiculite containers, and set them back in the incubator on misted paper towels. We let the hatchlings stay in the incubator until the egg sac falls off their bellies, and then transfer to paper towel lined 10 gal rubbermaid containers. Good luck with your new babies, a first hatching is a marvelous time!
Kathryn on hatchlings.
Oh, one idea--I don't remove the discarded egg shell until I have caught a corresponding baby: one shell, one baby. Both come out together. Thus, whenever there is a collapsed and empty eggshell, I
know that there is a baby hiding somewhere in the incubator (you think there is nowhere for them to hide in the incubator, but they will find a place!).
How long to keep in incubator after hatching? Until they run around and try to bite the hand that reaches for them... Actually, 2-3 days is good.
They generally won't eat at all for the first 3 days or even a week, so putting in live food is fruitless then, and the crickets can nibble on the babies. I give them 1/8 to 1/4 inch crickets (better than pinheads, which are too small) a few at a time initially, and take them out if the babies only look at them curiously, "I wonder what THAT was that ran by so fast". When they stop wondering and LEAP, they get more.
However, I start putting in moistened and finely chopped greens by the 4th of 5th day. It's better than a water dish, no matter how shallow. It's hard for them to drown in greens... And, this strategy has a payoff in that the young dragons eat their greens sooner and better than most...
Above all: Enjoy them. Go ahead and pick them up and admire them. I call babies the "Kliingon phase"; not only are they fearless--if you let one perch on your thumb, it will just CLING on there.... sputter, sputter, gasp, :-}
Ronnie on hatchlings
First off, they play opossum, so be prepared for the little guy to bolt faster than you might think. Usually when there is a yolk still attached, it takes 18 to 36 hours to be absorbed and for the sack to drop. Is he on the metal screen on the floor? If so, this could pose a serious problem if it snags the yolk sack and tears it off.
What I do with the hatchlings is place them in a plastic shoe box (Wal-Mart $.98) with a moist paper towel on the bottom. I mist the hatchling to clean all of the vermiculite off and leave him in the shoe box until the yolk sac is dropped, being sure not to let the paper towel dry out. I have a big incubator, so I just stick the shoe box inside to keep the air temps consistant with what he's used to. In your situation, I would improvise a little. The shoe box, or other high sided plastic container, should fit in the 30 gal. tank. Line the bottom of the tank with paper towels and simply transfer the hatchlings from the plastic container to the tank after the yolk sac drops. Set up the lights as you normally would, but I prefer to set the basking temps a little lower for hatchlings ( 90° or so). Replace the paper towel in the container with each hatchling or two, depending on how fast they hatch. (If you have time in between, fine, if not, then it's not that big of a deal).
They are pretty delicate, but by the same token you aren't likely to hurt it by picking it up unless you squeeze his rib cage. I just chase them into a corner and gently scoop them up, keeping my other hand over them to prevent them from leaping off half way through the transfer.
Can I handle him/her? To move from the incubator to the cage, sure. After you get him moved, I'd
keep the handling to a minimum for the first week, only picking them up to change the paper towels daily.
I try to move them out of the incubator as they hatch; others will leave them in the incubator for a day or two. It's up to you. Just be sure that they can't get into a cup of water and get into trouble (assuming there is one in the incubator). On the other hand, you do want to mist them at least once a day, with 2 or 3 times being better for the first month or so.
more from Kathryn on hatchlings
After the first egg hatches, it can take up to a week for the other to hatch, but most hatch within a 4 day period.
Some babies may still have an opening at the "umbilicus" (actually, the yolk stalk in reptiles) and may have a yolk sac still attached. The yolk sac can still be attached in many hatchlings--actually, in most, but in the majority the yolk has already been absorbed and the yolk sac drops off quite rapidly. The main thing to watch is that the yolk sac doesn't catch against anything and rupture prematurely. One thing that can cause rupture is a DRY paper towel--the yolk sac sticks to the paper, the baby tries to move away, and suffers an injury. So, if you keep them on paper towels, keep the paper towel moist, and keep the humidity high. A good place for such a baby is in the incubator until a day or two after the yolk sac diminishes. When you do move such a baby to his new environs afterward, be sure to keep him hydrated. You don't need to worry about feeding such a baby now, or even for a few days after his yolk sac contents disappear. He truly is living off his yolk. Just consider him a "premie"; prematurely born young of any species are a bit more delicate, but can grow into strong adults (some of your human friends were no doubt early birds).
I use a small spot of nail polish on hatchlings. Since it comes off when a BD sheds, I can easily tell who among a cage full of young'ns has had its first shed and who has not. I can also use some code to mark particular individuals. This is one good way of assessing how well the babies are developing. I never sell a hatchling until after it has become well established and had its first shed, usually after a month--indeed, I usually keep mine 2 months before giving them to one of the two pet stores that I let take my babies. I may sell some 1-month olds at shows, because at shows I can educate the person on their care on-the-spot. I put the dab of polish on the back near the tail--not on the head, where it can block light reception through the third eye.
Misting the babies often is good--they dehydrate easily, and I keep a watch on hatchling temperature and moisture. I do spray hatchlings much more than I do later kids or grownups, simply because they have such a larger surface to volume ratio and can dehydrate so easily. As a rule of thumb, if they DON'T lap when you spray, they didn't need to be sprayed (sounds like really irritating advice, telling you that something was unnecessary only after the fact, oh well.... guess if they stop lapping with the 4 th spraying, you can cut back to 3). Use a fine mist setting, rather than a "fire-hose" spray. I don't necessarily find 3-4 sprayings a day out of line for such little ones. Later, of course, once a day is generous. My Frilled dragons, on the other hand, will lap forever when sprayed. They occasionally need water delivered by needless syringe, drop by drop, don't know where they hold it (what do you mean, spoiled???).
One note of caution about using a water dish (learned the hard way...); the water must be VERY shallow. A hatchling can drown in 1/2 inch of water... Lately, I mist often rather than leaving a water dish in the dragon lair. I do occasionally let a tiny baby sit in 1/4 inch of water, but only under supervision, and then the water goes. The water dish is also a place where uneaten crickets invariably lodge and die. Dead crickets rapidly foul the water. The bacterial growth is amazingly rapid, and can be bad for the BDs. As a consequence of these two issues, drowning and fouling, I rarely give a water dish to any BD, regardless of age.
They will usually start eating within a week of hatching. I give food within three days out of the incubator. I give even hatchlings finely copped greens and veggies in the morning, then 1/4 inch crickets later in the day--several times a day, if possible. I also mist the veggies, which sometimes stimulates thirsty BDs to eat the veggies. All my babies scarf up veggies and greens as soon as they start eating anything. Several things that may help get them to eat veggies early: I chop the veggies and greens finely, I put them in a very shallow glass dish so they can actually see them, I put them in first thing in the morning, a half hour after their light comes on but well before they get their first crickets, I spray the veggies well with water (so they are the major source of water--they sip, accidently take a nip, and then take MORE nips because the first one tasted GOOD). Also, it helps to make sure the greens are in a little pile, since they have a great difficulty in picking a flat piece of greenery up from a flat surface. They get frustrated very easily. I also often put the crickets into the dish, so some dragons get their first intro to salad as an inadvertent side dish to insect. True, the new hatchlings don't eat huge amounts of veggies (their little tummies are so small, they could fill up completely on veggies while your back was turned, and may nibble more than you think), but the veggies serve the other vital purpose of feeding escaped crickets--which otherwise could chew on the babies' eyelids, etc. -yuck. I leave the veggies in overnight, so any overlooked crickets will have something to nibble on other than beardie.
Feeding them the greens early in the day, and making sure that greens are all they have to eat for the first hour or more of every day, seems to have one good consequence: my BDs all eat their veggies from the onset, unlike many other youngsters, who don't eat veggies until they are big. I think mine profit from the more varied diet. With this regimen of feeding veggies early, my babies seem to start eating their veggies earlier than most, and thus start getting the good veggy nutrition early. A couple of people on the list who've followed this advice have also had their BDs eat veggies early--like Pete. (Right, Pete??)
About substrata: I use paper towels with babies and youngsters. I change the paper towels every day, thus removing any excrement, and clean the tank thoroughly once a week (actually changing the tank for a clean one and rinsing all furniture). One advantage of the paper towel regimen--some (not all) of my adults have learned that paper towels mean toilet; they will preferentially go on paper towels. I keep paper towels in a corner of their tanks, even though their substratum is now rabbit pellets. This "trained response" really helps with daily cage-cleaning. Of course, some BDs never figure this out...
If you can tolerate fruit flies in the house, putting a little bit of ripe banana or other fruit in the tank (in a place the babies can't actually get stuck in it) will attract fruit flies into the cage (use a more open-mesh top). The babies are entranced by tiny flying objects. First they merely look puzzled or startled, "what WAS that!!", Then they will run after them. Of course, the fruit flies don't offer than much sustenance, but it is variety, and they do get to "hunt", which is probably fun for them--and even more fun to watch...
You don't need pinhead crickets--1/4 inch will do. Of course, the uneaten pinheads will grow up...
Another suggestion--if you want to hand feed them, approach with your hand held fairly low. They have an innate "fear of something big coming from above" response. They will be able to eat 1/4 inch crickets (no need for 1/8 inch or pinheads) once they begin eating. Dust the crickets by putting them in a plastic bag, adding some of the very fine Rep-Cal, and shaking, just like with adult crickets.
Have fun, the babies are always so adorable.
The photo below, kindly supplied by Tammy Belicic ("Tammy & the zoo"),
shows a hatchling next to a quarter, for scale.