It’s understood that up to 60,000 chickens have been culled due to the “possible” use of unauthorised antibiotics on two farms supplying Carton Bros.

The company sells chicken under the Manor Farm brand, and a statement from the company said following its own tests where concerns were raised, it notified the Department of Agriculture immediately and further testing was carried out.

“Subsequently, and out of an abundance of caution, all birds from these two farms were processed and where there was any doubt over the suitability of the birds for the food chain, the birds were removed and disposed of, under the supervision of Department of Agriculture,” a spokesperson for Carton Bros said.

“As a result, any potential threat to food safety has been avoided by these proactive and precautionary measures.”

The business works with 180 farms and the cull is unlikely to have an impact on supplies to shop shelves.