The number of ducks being reared for food without access to basics such as natural light and water to bathe in has shot up by almost 20 per cent since 2010, animal welfare campaigners have warned.
They say less than a third are kept in conditions which meet the RSPCA's higher Freedom Food welfare standards, compared with half of those farmed two years ago.
This comes as the RSPCA launches its "Like a Duck to Water" campaign to improve the welfare of Britain's "forgotten farm animal" after it was revealed that ducks are the animals consumers are least concerned about when it comes to welfare.
In a poll of 2,212 people carried out by YouGov, 84 per cent said they had never thought about how farmed ducks were reared. However, 80 per cent of people agreed with the statement, "I am appalled that ducks farmed for their meat never get access to bathing water".
There are no legal requirements to provide open water for ducks to bathe in, or bedding such as straw, or natural light, and there is no limit on how many of the birds can be kept in one space, the RSPCA says, while even ducks raised to the standards of the British Poultry Council's "duck assurance scheme" do not have to be given bathing water.
Dr Marc Cooper, a duck welfare expert from the RSPCA's farm animal science team, said: "Ducks are waterfowl; they need bathing water. Why else would they have webbed feet?
The campaign, which calls on consumers to urge supermarkets only to stock duck that has been given access to bathing water, has met with criticism from the BPC, which said its assurance scheme already demanded sufficient water to meet a duck's needs.
Duck farming for meat is increasing in the UK. There were 14.7 million ducks reared for meat last year compared with 13 million in 2010.