Animal rights charity Viva! is putting pressure on supermarket giant Tesco to drop one of its suppliers.
Undercover footage obtained by Viva! of Hogwood Farm revealed grim conditions - including pigs eating the rotting corpses of dead pigs who had not been removed.
According to Viva! Founder Juliet Gellatley: "Hogwood hides a catalogue of pain and suffering, some of the worst conditions we have seen.
"Our footage shows cruel farrowing crates, which trap the pregnant sow in a metal pen when she could be walking over a field to make a nest out of twigs for her piglets.
"The other pens are overcrowded and the pigs show signs of stress. They are stuck in with dead and extremely sick pigs, dumped in gangways with no access to food or water.
"Others were dying in a filthy shed covered in cobwebs."
Viva! has launched a petition asking Tesco to cut ties with the supplier. The petition has attracted more than 31,000 signatures so far.
Tesco has so far continued to support the farm.
A statement from the supermarket says: "We take animal welfare extremely seriously and expect producers to meet recognised standards as well as our own stringent, industry leading requirements.
"Our dedicated agriculture team, Red Tractor and the Animal and Plant Health Agency visit farms regularly and any claims standards have not been reached are fully investigated."