I think if you wait 40 minecraft days the egg will hatch. But you have to saddle the dragon within 5-10 minutes or else it will become hostile.
Just watch these cool You tube videos and you will get what you want
1 Minecraft BABY ENDER DRAGONS! Hatch & Fly!
2. If you have two adult Ender Dragons, you can make them breed. You do this by right clicking both with an Ender Pearl, and they will breed. Instead of a baby Ender Dragon to show up, a Ender Dragon Egg will show up. You have to put the Ender Dragon egg in an incubator in order to breed it, it takes around 10 days to breed.
Chk this link it is a minecraft forumhttp://www.370sou.com/how-do-i-hatch-an-ender-dragon-egg-on-minecraft-xbox-360-edition-7785/
You might be interested in this conversation part where it says
First you must get the egg. Then make a saddle and place the egg. Then take your saddle and click the ender dragon egg and use raw fish to tame it. And thats how you do it! This info was from my older cousin cause he did the same thing. So have fun with your new pet dragon!
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