Animal rights activists in France have released shocking footage of ducklings being mutilated and killed to produce foie gras in the hope of persuading more diners to desert the favoured Christmas delicacy over this festive period.

The video was secretly filmed inside a hatchery in the north-western Pays de la Loire region by a group named L214.

It shows workers separating male from female ducklings, moments after they emerge from their egg. Females are then flung into a masher and killed, although some show signs of life as they emerge from the other side of machine.

The activist group explained female ducks are no good for foie gras, as their liver, from which the luxury food product is made, is too small. They are therefore killed en mass just after birth. About 6,000 pass through the hatchery's masher every day, according to L214.

The surviving males are fitted into the rotating carousel of a machine that chops their beaks off with white-hot metal, so that they will not injure each other during the force-fattening period that precedes slaughter. "The cruelty of force feeding was already known," said L214 spokesperson Brigitte Gothière introducing the clip. "Today we discover other horrors of the foie gras production".

The delicatessen is traditionally France's favourite Christmas dish. A recent survey however showed that a growing number of Frenchmen were giving up the savoury pâté due to the animal suffering involved in its production. Exactly a third of respondents to a YouGov poll said they refused to buy foie gras for ethical reasons, a four-point increase on 2014.

In October, an abattoir was temporarily shut and an investigation launched after L214 released a similar video showing cruel slaughter practices.