A poultry farm could switch from rearing turkeys to producing 2.5m chickens year.

GNR Farms has applied to redevelop its 20-acre site at Setchey, near King’s Lynn, which currently produces 90,000 turkeys a year.

Seven of the 13 sheds on land off Setch Road will be “decommissioned” and used for storage, while the remaining six will be upgraded and six new broiler sheds built alongside them.

An environmental statement says: “The existing turkey enterprise is no longer economically viable.

“Changes in the turkey market and the significant cost of upgrading the ageing buildings mean that GNR Farms is unable to continue the current operation sustainably.

“The redevelopment will replace the turkey enterprise with a modern broiler chicken unit that is more efficient, operated to higher animal welfare standards and designed to minimise its environmental impact.”

Planning papers say the 12 buildings will house 330,000 chickens and produce 2.5m birds a year.

Each building will be fitted with mechanical ventilation, feed and water systems “aiming to improve bird welfare and environmental performance” on the site.

A planning statement said the new layout will increase the distance from the poultry shed to the nearest house from 130m to 190m.

The broiler operation would run on a 48-day cycle, with chicks delivered at one day old and reared for 38 days.

Manure produced on-site would not be spread on land but supplied to a refinery in Lincolnshire which would convert it into biogas and fertiliser.

Planning papers say the Environment Agency has already granted an environmental permit to convert the site.

The environmental statement adds: “The new broiler enterprise, with its modern high-speed ventilation fans and lower stocking density, is predicted to produce significantly less odour than the existing turkey enterprise.”

A new wildlife pond and wildflower areas will be created, while 90 native trees will also be planted on the site as part of a package of habitat improvements.

A decision from West Norfolk Council is expected later this year.