They will put on about three times as much weight in about three months. As their gender can't be determined yet they are unnamed.
"We haven't decided on names yet as we are waiting for their little personalities to start shining through," said penguin team leader Laura Seaman.
Gentoo penguins are the third largest penguin species, known for their charisma and swimming abilities. Photo / Alex burton
"The larger chick is being raised by first-time parents Humphrey and Myrtle, who have been doing an excellent job, which is lovely to see. The smaller chick is being raised by seasoned parents Tua and Al, who have parenting down pat," she added.
Gentoo penguins are the third largest penguin species, known for their charisma and swimming abilities. It won't be long before the new chicks have fledged and can begin learning how to swim.
The Sub-Antarctic area includes Emperor penguins. Photo / Alex Burton
The name gentoo has two possible sources: English settlers in India often used the term for turban-wearing Hindus (the birds have a white bonnet on their heads) and it is also thought the names comes from Juanito, the Spanish for Johnny as it was once called the Johnny penguin.
Whether the chicks are Johnny or Juanita, they're on view now to the public in the Sub-Antarctic penguin colony at Kelly Tarlton's