Lessons learned with incubation

premature turtle egg, broken egg, honduran wood turtle, rhinoclemmys pulcherrima

Most of the time with my animals I get to talk about all the positives; the progress, the new additions, the breeding successes. As with anything, there are the rough parts too. When I started Insectivore, transparency was my goal – to share my experiences good and bad and hopefully help others learn from any mistakes along the way. So in the interests of transparency, and rather painfully, I have to share how I came to lose 5 clutches of turtle eggs, and the steps I took to save what I could.

Those of you that have followed this website will know that my main breeding focus has been the Honduran Wood Turtle (Rhinoclemmys pulcherrima incisa), which lay 2 eggs per clutch, and hatch after a 3 month incubation. This is my third year breeding them, and if I’m honest I’d started to take the incubation for granted. My two breeding pairs have a very high viability, so with nearly all the eggs I get, keeping them in plastic livefood tubs with some damp vermiculite and sticking in the incubator at 28ÂșC almost inevitably results in hatchlings.

With so many eggs already this year, I decided instead of multiple tubs I would instead use a bigger Braplast tub to keep all the clutches together. In hindsight, “putting all your eggs in one basket” is an obviously disasterous idea. If you are not familiar with Braplast tubs, they have two big differences compared to livefood tubs. Firstly, they have fewer ventilation holes, and secondly, all the ventilation is in the lid of the tub, in comparison to livefood tubs with slotted sides. In short, this resulted in the lack of venilation for the vermiculite layer in the tub, but I also believe that condensation build up in the incubator was dripping onto the lid of the Braplast container, and seeping in through the top holes. The end result – sopping wet vermiculite, and some very wet eggs.

Had I been keeping a closer eye on the eggs, perhaps I wouldn’t have lost most of the batch. At first I noticed some of the eggs developing hairline cracks, which I mistakenly attributed to a lack of calcium in my breeding female’s diets. I used nail polish to seal the cracks (a very good fix for little bits of damage to the incubating eggs), increased calcium additives for my adults, and continued with the incubation. It was only after trying to candle the eggs a couple of weeks later that I discovered almost all had cracked due to wetness and were ruined. Out of the 10 eggs, 3 remained intact and I have continued incubating in a livefood tub (although at time of writing all look infertile), and 2 turtles hatched prematurely. Sadly, I lost the smaller of the two, however the larger of the premature hatchlings gradually absorbed the yolk sac over the course of a few days, and is now a perfectly normal baby turtle.

The biggest concern for me with the premature hatchling was the large yolk sac, which could have easily been damaged, resulting in bacterial infection. Having removed the baby turtle from the wet vermiculite, I placed it in a egg-sized depression made from stretched clingfilm, and suspended in a plastic cup. By cutting the base of the plastic cup, it allowed me to view the hatchling from underneath and see the absorption of the yolk day-to-day. I believe the cling film pouch replicated the security of the egg shell, keeping the turtle from wriggling, and preventing water loss and dehydration.

What surprised me the most was the speed at which the yolk was absorbed, being completely used in a matter of 3-4 days. This turtle is now a regular, healthy Rhinoclemmys hatchling, feeding well and soon ready to go to a new home. Needless to say, I have returned to my previous method of egg incubation, keeping only 1 or 2 clutches of eggs per container, and checking each clutch regularly so I can respond to any problems as they happen.

I hope this update proves useful in some respect, whilst it’s not something I ever wanted to share it could hopefully help others avoid the same problems. Should you have any further questions feel free to drop me an email using the link below as always.

Paul Edmondson

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