The first chick emerged three weeks ago and there have been steady hatchings since then. The latest occurred on Tuesday morning from a Tongariro egg.
A chick from Maungataniwha near Napier hatched on Monday night and two chicks hatched on Sunday evening, one from Omataroa in Whakatane and the other from Whirinaki forest.
As part of BNZ Operation Nest Egg, eggs are gathered from nests to save them from predators and are incubated and cared for at Kiwi Encounter.
The kiwis are returned to the wild when they weigh a healthy 1kg.
Rainbow Springs has been involved in Operation Next Egg since 1995, beginning with the arrival of a single abandoned kiwi egg.
Kiwi Encounter is the only purpose-built kiwi conservation facility open to the public in the world.
It is sponsored by the BNZ Save the Kiwi Trust, a charity partnership between BNZ, the Department of Conservation and Forest and Bird.
Captive breeding programmes are also run from the site along with rehabilitation work for birds injured in the wild.
More than 100 North Island brown kiwi chicks are successfully hatched each year at Kiwi Encounter.