Dragon eggs are extremely rare. They are usually laid in a nest of bark and the mother will rest on them until they hatch. She will only leave the egg in a situation where she is scared or feels she can trust the location to be completely safe.
Here's what a dragon egg may look like:
Reasons that an egg may be abandoned
If a dragon egg is found it MUST be stored in a warm dark place as if it was underneath mum dragon. The warmth will help to make it hatch. Under no circumstances put it in a cold light place. This can slow down the hatching process.!
On some occasions a dragon may trust birds to raise or look after her egg for a short while until she returns. This is because Birds are considered by dragons to be the closest animals to their species, even though some people think that dragons are closer to crocodiles or snakes.