Many hobbyists enjoy incubating their turtle's eggs artificially. Below are some general guidelines and simple techniques that can lead to successful incubation.
Turtle and tortoise eggs can be hard-shelled or relatively soft depending on the particular species. New-laid turtle and tortoise eggs tend to have a bluish-white hue. Within 2 days, the eggs of many species will "chalk over", that is the shell will become a more opaque, chalky, white color. Some eggs of water turtles and semi-terrestrial species will "band", that is the middle third or so of a somewhat elongated egg will chalk over.
During incubation turtle and tortoise eggs can be candled to check on their development. Hold the egg over a pencil light or other narrow beam of light. The yolk can be seen resting on the bottom of the egg. Over time, a network of blood vessels may be seen above it.
The time taken for eggs to hatch depends upon both the type of turtle and the incubation temperature. The eggs may not all hatch at once, so be sure to leave any unhatched eggs to incubate longer, just in case.
Recovering the Eggs
When the female has finished laying, open the nest and carefully remove the eggs. A clean paintbrush is a useful tool for uncovering the eggs. If the nest has been filled in, dig out the soil using a spoon, paintbrush or other small utensil. The dirt may be packed down tightly, and caution is needed to avoid breaking the eggs.
After carefully removing the eggs from the nest, lightly mark a cross or number on the top of each one with a pencil. At some stages in the their development, turning a turtle or tortoise egg can result in the death of the growing embryo, and the pencil mark makes it easier to maintain the eggs in the same orientation as they were laid. Gently brush off soil and debris from the eggs with a tissue or paper towel, and transport them to the incubator.
A variety of incubation set-ups have been used to successfully incubate turtle and tortoise eggs. The important factor is that the incubator be able to maintain the appropriate temperature and humidity. Generally, water turtles eggs require higher humidity than terrestrial turtles and desert species.