The most baffling theories held by youngsters include eggs being produced by sheep, yoghurts containing turkey or duck – and bacon the product of horses.
Fewer than one in four know that beef burgers are sourced from cows, with 29 per cent saying beef burgers come from pigs. Some youngsters think burgers come from McDonald's or Burger King.
Of the 1,100 Westcountry youngsters between the ages of six and eight questioned, almost two-thirds struggle to say where the food that they regularly eat comes from.
The research was commissioned to coincide with the launch of a campaign to encourage children in the region to grow their own produce.
Launched today at Highfield Farm in Topsham, near Exeter, Dig Down South West aims to help create 50 vegetable gardens in schools across Cornwall, Devon, Somerset and Dorset.
Campaigners are keen to promote the value of children understanding the source of their food, nurturing their own produce and learning how to live a more sustainable life for the future.
Television personality and gardening expert Charlie Dimmock has put her name to the campaign.
She said: "I think that Dig Down South West is a really fantastic way of getting children involved in growing their own vegetables. Youngsters love getting their hands dirty and I'm sure this will be really popular.
"It provides the opportunity for them to be creative and the children can see the progress of what they're growing, and in the process of growing, they learn a whole lot more."
The driving force behind the campaign is rural insurance firm Cornish Mutual, which also commissioned the survey.
Alan Goddard, managing director of firm, said he was "surprised" by the findings, particularly since farming and the countryside was at the heart of the South West economy.
Other bizarre responses include pupils believing rabbits, plastic or sheep were the main ingredient of crisps – and some think ice-cream is made with cheese, air, fish or potatoes.
Encouragingly, nearly 70 per cent of youngsters give the correct answer of five portions of fruit or vegetables a day as part of a healthy diet.
Mr Goddard said: "It's really important that we reach children at this young age.
"Clearly they do have an understanding. However, there are some huge gaps in their knowledge and we hope that through Dig Down South West, we can help to build on what they know and get them enthusiastic about local produce."
Topsham School in Devon is one of the first schools getting involved and its pupils have visited Highfield Farm many times.
Teacher Justin Vernon said: "Growing vegetables is the next exciting step, allowing us to expand on what we've been doing in our allotment patch at school in recent years.
"We're really looking forward to not only growing the crops but also thinking about how we can use them in school, for example, establishing a cookery club or using them in school meals and for snacks."
For more information, visit www.digdownsw.co.uk