Chicken allergies are not uncommon, but what is uncommon is how young you are seeing problems. My pup started having issues at that age too, and I really think it was all because the original owners didn’t do enough about the heavy worm load he had, and it damaged his intestines.
Even if it isn’t a food allergy issue, feeding different foods isn’t a bad thing. It helps to support a wider variety of probiotics in the gut. So try to find a food that is as different as possible ingredient wise to try, just in case. And look at the possibility of environmental issues as well, which also don’t normally develop this young, but they are both immune issues and a heavy worm load can trigger the immune system.
