Something that is ‘hypoallergenic’ is something that is relatively unlikely to cause an allergic reaction.
There are certain foods which are known to be the most common when it comes to allergies and intolerances for dogs, such as grains, chicken and beef.
Generally those proteins that are labelled ‘hypoallergenic’ are actually ‘novel’ proteins – ones that the dog has been unlikely to have eaten before and therefore would be less likely to cause a reaction.
It is almost impossible to say what proteins are ‘hypoallergenic’ as this would vary from dog to dog and what they have previously been exposed to.
Generally the most novel proteins include lamb, venison and rabbit – which can be a good starting point if you are investigating your dog’s potential intolerance or allergy.