Secretly-filmed footage taken at Hall Farm in Hingham, Norfolk, UK, shows the birds being herded onto crates to be taken away for slaughter. But some workers are seen picking ducks up by their necks and swinging them before throwing them back into the flock.
As well as sick and injured birds, we also discovered dead birds left to rot among the flock. Those that had been removed were found decomposing in a skip instead of being safely put in bags to avoid contamination.
After viewing the footage, the RSPCA told Sky News the pictures were "absolutely shocking".