For every egg or hatchling you killed, Zu will get 8 stacks of Buff. And at 16 stacks, Zu will wipe the whole part with his body slam. Here is what our group has been doing:

1/Have everyone marked focus on Zu to watch for his stacks.
2/Kill one of the glowing egg and take down and kite the others hatchling but not kill.
3/ Wait for the stack get below 6, then kill the adds.
4/Rise and repeat.

Here is a couple things you need to remember:

1/ When Zu fly to the sky, it is a very good chance to kill all the adds because Zu wont get stack even if you kill them all during the phase.
2/Always kill the shooter first. And kite the fighter and kill them later when safe.
3/ When Zu takes off the ground, have your Tank stay away from the group because he will do AOE and target the tank (or whoever got the most aggro at that time).

If you follow these hint, you should be able to take down Zu with no trouble.