You should seperate the egg from the turtles to avoid it being rolled around or crushed. You can incubate the egg in a vented container filled half way with damp perlite or vermiculite. The temp can range from 75-80 degrees. Be careful to pick the egg up and place it in the incubation container without rolling it or turning it. It should only take between 45 and 90 days to hatch if it is fertile.