The gentoo penguins have so far produced 22 chicks, which began hatching last month, at the city zoo.
The penguins are listed as “near threatened” on the International Union for Conservation of Nature (IUCN) Red List because of human activity.
In the wild the birds are at risk from illegal egg collection, oil exploration and tourists, which affect breeding pairs.
As the chicks grow, the keepers observe their weight gains to make sure they’re getting enough food.
“The chicks are all growing so quickly” said Dawn Nicoll, Senior Penguin Keeper at RZSS Edinburgh Zoo.
“Whilst some are still quite small, weighing just over 500g, the chicks which hatched at the beginning of May are getting really big, weighing as much as 3kg.”
The penguin breeding season began in early March with the annual placing of the nest rings and pebbles into Penguins Rock.
Romantic male penguins then sought out the best looking and smoothest pebbles to ‘propose’ to their potential mates.
Dawn said: “By weighing the chicks regularly we can monitor their health and make sure they are getting enough food.
“Once the chicks get a bit older they will leave the nest site and join a crèche away from their parents, where they will learn all the essential penguin skills such as how to feed and swim.”
A focal point of Edinburgh Zoo for over a century, the birds live in the largest outdoor penguin pool in Europe.
They were one of the first species to arrive at the Scottish Zoo, paving the way for global recognition when they were the first outside the southern hemisphere to breed king penguins.
The world famous daily Penguin Parade began in 1951 when a keeper accidentally left the gate open and the penguins went for a short walk and then returned to their enclosure.
Edinburgh keepers still open the gate every day at 2.15pm and birds waddle out of their enclosure to the delight of visitors.