A chicken factory is facing closure, putting 730 jobs at risk.
Poultry giant 2 Sisters Food Group said the site in Llangefni, Anglesey, was old and would require significant investment to bring it up to the same standard as its other locations.
The firm also said Llangefni was one of its smallest sites and products could be made more efficiently elsewhere.
It added that it would speak with employees to explore the options before making final decisions on closure.
The company's chief executive Ronald Kers said 2 Sisters would try to find alternative work for everyone.
This would be with other local employers, or at its other sites including Sandycroft in Flintshire and Rogerstone, Newport.
However, he admitted redundancies were likely.
"We will do our best to redeploy as many people as possible, but I think it will be unrealistic to assume that we can redeploy everyone, so we will be looking at redundancies," he said.
"We realise that this is absolutely terrible news for those families and we'll do all that we can to listen to the ideas before we make any final decision.
"However, it is also our responsibility to the other 13,000 people that we employ to make sure that our business is sustainable as a total division."
Mr Kers said a consultation with unions would explore the best way forward, but left little prospect of the factory staying open.
"I would never rule anything out, but the fact of the matter is that the site is old," he added.
"It's over 50 years old, it's small, it's inefficient, the transport costs are too high.
"So if there was an easy solution, we would have definitely explored that in more detail. Unfortunately, the picture is bleak."
The planned closure follows a review by 2 Sisters of its UK poultry division to overcome "challenges facing the food manufacturing sector".
Its review described the Llangefni site, which it bought in 2013, as "not sustainable" and lacking space to be efficient, despite £5m being invested there.
"The cost to produce here is higher, and it would require significant investment to bring it up to the standards of our other factories," a statement said.
"Our products can be made more efficiently elsewhere across our estate.
Peter Hughes, the regional secretary of Unite Wales, said: "It came as a complete shock for the workforce and for ourselves.
"We believe there's viable employment here. They're making a profit, so ultimately there should be jobs on Anglesey.
"This place has been here over 50 years and employed people over that lifespan. So why now have they made the decision to move out of Anglesey?"
Economy Minister Vaughan Gething said: "I met with the local authority this morning once we were made aware of the news.
"We are in contact with the company and trade union to understand the implications of this surprise announcement."
Mr Kers previously warned in an interview with The Grocer in December about the challenges faced in the industry.
The company's last published accounts show it made a £95.5m loss to 31 July, 2021.
Farmers' Union of Wales chief executive Guto Bebb, said: "The closure of this food processing site is a blow for the local community, the economy and for food processing in Wales.
"We are naturally concerned about the impact this will have on our food supply chains as we are losing another food processing site in Wales."
Ynys Mon MP Virginia Crosbie said the planned closure was "devastating news".
She added: "I will be speaking to the unions very soon and I would support a task group being set up to help navigate what is happening and what could happen, if the factory closes.
"I am also meeting with the chancellor this morning and I will be raising what is happening on the island with him as a matter of urgency."
Anglesey council leader Llinos Medi said action needed to be taken to support workers and their families.
"Now is also the time for urgent and decisive action from both UK and Welsh governments - both of which can facilitate more investment and much needed jobs on the island," she added.
Workers in Llangefni are bearing the brunt of the cost pressures hitting 2 Sisters.
The site on Anglesey did not have the capacity to be improved, the company said, which made it a target for closure as the owners looked for efficiencies.
Some feared this was coming.
There was an "existential threat" facing the 2 Sisters business model in December, when the CEO Ronald Kers warned that it was being hit by rising costs and the bird flu outbreak.
Production costs had risen by 35% year on year and the firm had been losing tens of millions of pounds, but Mr Kers warned the "worst was yet to come".
Staff in Llangefni are feeling the pain of the 2 Sisters plan to address the problem.
But the island's broader economy will also take a hit. While jobs are being lost at the poultry plant, local people have faced the bottleneck traffic of the closure of the Menai Bridge and the continuing uncertainty about whether a new nuclear power plant will be built at Wylfa.
2 Sisters workers need support in finding new jobs, but they'll be doing so as many other businesses review their plans amid high inflation and a looming recession.