We thought that our three APBTs had food allergies because they weren't able to get use to their food. They had soft stool the whole time they were eating it and their stool was almost slimy looking (sorry, I know that's gross). We didn't suddenly change their food or anything like that, we don't give them people food, though they do get some plain yogurt with all of the active cultures in it every now and then, nothing had changed, but they just weren't getting any better. They were eating and drinking like normal and they were throwing up or acting sick, they just had soft stool all of the time. So, we decided to switch them to a food that is good for dogs with food allergies. We switched them from Natural Balance Ultra Premium dry dog food to Natural Balance Duck and Potato dry formula. So, we switched them over slowly and got them eating the new food. They did seem to be making an improvement, but when we went to go get more food they were out of the Duck and Potato, so we got the Ultra Premium. They had some Duck and Potato left still so we were able to mix that with the other so they didn't get sick. Anyway, we are about to switch them back to the Duck and Potato so that they can have some time to really get use to it and see if that helps. But before we switched their food again, I wanted to see if it sounds like they do have food allergies or not. So, how can you tell if a dog has food allergies? Is this something I would have to talk to the vet about or are there ways I can tell and just put them on a food that's for dogs with food allergies? Also, if they do have food allergies, will there still be some foods that they can't eat, even if it is a food that's good for food allergies? Like Natural Balance has the Duck and Potato that's good for food allergies and they also have Sweet Potato and Fish that's good for food allergies. Would it be possible that one would work better for them than the other if they do have food allergies?