Babthorpe Hall Farm, near Selby in North Yorkshire, said the free-range hens had come to the end of their working lives.
Owner Sheena Seels said there had already been a bit of interest in the birds since her daughter Ellie posted a message on social media.
"It's been a very positive response, 300 have gone this morning," she said.
Ms Seels said the mass sale of birds was quite common in the egg industry, as producers restocked with younger birds.
"Once they come to 72 weeks their shell quality goes as the hens get older," she said.
The brood of Bovan Brown hens are described as having "lovely friendly temperaments".
Ms Seels said potential buyers needed to have enough space for the birds to wander about and they would be better with other chickens.
"They do like company. They are very sociable," she said.
"They look after themselves, so long as they are fed and watered."
About 10,000 live chickens have been put up for sale to the public to stop them from being slaughtered.