Maja Skilling says although she is only 12, she's not afraid of taking on the big guns.
"I may only be a child, but I want to make a difference. I want Countdown to stop selling these cage eggs once and for all."
The keen animal lover last month launched a change.org petition calling for the supermarket giant to ban the sale of cage and colony eggs, like its sister company Woolworths has done across the ditch.
She's since gathered close to 15,000 signatures and the backing of animal welfare organisation SAFE, which is helping promote her cause.
Maja said she began to learn about the "cruel and inhumane" practice of battery farming after getting four of her own chickens a few years ago.
"It's a sad and disturbing life for such curious and friendly birds."
Maja said the issue was not just about the supermarkets, but the suppliers too.
"My ultimate dream is for there to be no more caged hen farming in New Zealand. It would change the way the whole industry works.
"They have to give their suppliers time to change to free range, that's the ultimate ideal. Some farms are better than others but they should find the most ethical eggs. Anything's better than caged farming."
Her stance has won public praise, with social media posters calling her inspirational and compassionate. Maja's mother, Justine Skilling, is suitably among those proud of her daughter.
"She is young, but passionate and principled and she is standing up and taking action," she said.
She says even Maja's classmates and teacher have pledged their support and have been active in signing the petition.
"Quite a few of her friends have gotten into eating free range eggs and eating vegetarian," she said.
SAFE spokeswoman Marianne Macdonald said their campaign was focused solely on Countdown because of Woolworths's stance in Australia.
Countdown spokesman James Walker congratulated Maja for expressing her views but said they had no plan to stop selling colony eggs.
"We have told SAFE we cannot make a genuine commitment by when we can go completely cage-free as it is not clear where this supply would come from. This would also result in more expensive eggs, and major supply shortages as we have seen in Australia last month."
Mr Walker said the company had been increasing the amount of free range and barn eggs on its shelves to 40 per cent, a number that was growing.
He said Woolworths' pledge to go cage-free was made in a market with a different supply chain and regulations. In Australia, farmers are allowed four times as many birds per hectare to qualify as free range.
Countdown rival Foodstuffs - which owns the Pak'N Save, New World and Four Square brands - said it also had no plans to stop selling colony eggs as they needed to offer a variety of options for customers.
• The existing battery cages give 550sq cm
• Colony battery cages have up to 60 birds in one cage