About 1,000 "vulnerable" day-old chicks have been abandoned in a field in Lincolnshire, sparking an RSPCA investigation.
Officers of the animal welfare charity were called after the chicks were left in a field near Crowland on Friday.
Insp Justin Stubbs of the RSPCA said: "I have never seen anything like it; it was just a sea of yellow. And the noise was unbelievable."
He said some birds were dead but most "did not appear to be suffering".
However, some of the birds had to be humanely put down.
'Unbelievable'
"For someone to dump these vulnerable chicks is unbelievable," Insp Stubbs said.
The chicks were thought to have come from a commercial producer nearby but could have been abandoned by someone else, said the RSPCA.
People in the area helped round up the birds into boxes and the breeder collected the survivors and took them back to its unit.
The RSPCA said the chick producer was co-operating with its investigation.
It is appealing for anyone with information to get in touch.