Absolutely. I used to work in a health pet food store, and we saw allergies to food develop all the time. I can't remember exactly why though, but I think it had something to do with chicken and/or beef being too widely fed, and pets were starting to become allergic to it.
I would change the meat source to something other than beef or chicken - and if your friend feeds raw, then I would eliminate all the other ingredients except for the meat source until you figure out if it actually is the meat source, because it could be something else in the food as well. Then I would start adding food back to see the dogs reaction to the other ingredients.
Honestly, I would also recommend a holistic vet who practices conventional medicine. They treat the animal as a whole, and will look at all aspects of the dog to determine a problem.