A top-end supermarket chain is recalling organic eggs from one of its suppliers, after discovering the chickens had eaten lead shot.

Waitrose said it was recalling the eggs from one farm because of fears of lead contamination.

A supermarket spokeswoman said some Blacktail Columbian eggs with the code OUK20137 stamped on them were being recalled, but the majority of its organic eggs were not affected.

“We can confirm that some chickens from a flock on one farm supplying Waitrose with Blacktail Columbian organic eggs have been found to have consumed lead shot,” she said.

“This is thought to have been caused by shot from a nearby clay pigeon shoot getting into the free-range enclosure.”

The chickens became ill after wandering on to a field used for clay pigeon shooting. A vet was called, and they were discovered to have higer-than-normal levels of lead in their blood.

Customers with the affected organic eggs were advised to return them to Waitrose for a full refund.

In March, trading standard officers investigated claims that Waitrose had wrongly labelled bacon as coming from a rare native breed of pig, when it was actually “mongrel meat”.

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