"This was an honest mistake which our bakers have fixed.
"While only the tiniest trace of this product was used in our pies - 0.0023 per cent - we understand the principle here and no future vegan pies, including the ones being baked today, will contain this product.
"To demonstrate how seriously we take this, a production run of these pies using this ingredient are now being donated to charity rather than sold at Z sites. Thanks again for bringing this to our attention."
The pie, which won a customer competition to be sold in Z petrol stations over the summer holiday period, had sold in the thousands in its first five days on the racks - with some stores selling out.
Gemma McLeod, a health food blogger from Auckland, beat out stiff competition to be the vegan winner, with four of the top five entries being vegan.
The woman who discovered ground-up poultry feathers in the ingredients list for the Mexican pie said members of the Vegans New Zealand Facebook group were "overwhelmingly posting support online for Z Energy".
"We are pleased that Z Energy have been so upfront and honest and immediately taken responsibility for their mistake (or the mistake of whoever they contract to bake their pies)," she said.
"They have remedied the situation and have today started baking a new batch of pies without the E920. No pies containing the E920 are on sale and the new batch produced has been donated to charity."Other vegans had found ingredients derived from animal ingredients after purchasing and consuming products, she said.
"It's an easy mistake to make and simply highlights how "hidden" a lot of ingredients are. I assume many non-vegans would be disgusted to learn their food is made from ground-up feathers too."
The woman said a petition had also been started to make the vegan product a permanent addition to Z Energy's piewarmers.
It had been signed 388 times since it was started earlier today.
The limited-edition pie - a success around the country - is on sale until January 24.