The family behind East Anglian poultry business Crown Chicken is set for a multimillion-pound windfall after it was sold to UK pork producer Cranswick in a £40m deal.

Crown Chicken was set up in 1951 and is currently chaired by David Thacker – son of the founder, Fred Thacker – who owns a majority of the shares. Thacker will step down once the deal is completed, but his fellow directors Nigel Armes and Matthew Ward, who own stakes in the business, will stay on.

The deal follows Cranswick’s purchase of Benson Park, a leading poultry producer, in October 2014 for an undisclosed amount.

Adam Couch, the chief executive of Cranswick, has said: “This acquisition represents important progress in our long-term growth strategy of developing new product channels in both pork and other proteins.”

Crown “is a well-respected operator in the UK poultry sector,” said Couch. The company breeds and processes chicken for the food service, manufacturing, wholesale and grocery markets. Customers include Iceland, Booker Group and Nisa.

Couch said the deal “represents an excellent opportunity for Cranswick to continue the development of its UK poultry business, building on the highly successful acquisition of Benson Park”.

Crown Chicken has also invested in its own milling operation, which supplies its chicken feed requirements, as well as selling to pig and poultry producers in East Anglia.

Last year, it had revenues of £83.8m and earnings of £6.6m, employing a workforce of 400.

Analysts at broker Liberum said: “The acquisition ... gives Cranswick a foothold to expand into poultry processing, adding another leg to the company’s growth outlook beyond its market share gains and rising exports in pork.”