Activists hope the web page will be used by consumers to make informed choices about where they shop and the products they buy.
Called ‘The Conscientious Consumer’, the section also provides an overview of the logos found on food packaging, including the little red tractor.
The RSPCA said it wanted to unravel “confusing messages around ambiguous food labelling, which often obscures the truth about how animal welfare-friendly some products actually are”.
Chloe Alexander, RSPCA campaigner, said: “If enough people boycott certain products or stores, supermarkets might in turn raise welfare standards.”
The guide has been gathered from RSPCA surveys carried out over the past two years. M&S, the Co-op and Waitrose were singled out for praise.