According to the official website of KFC, previously known as Kentucky Fried Chicken, the gravy is not actually vegetarian. They make use of a mixture of gravy powder with some crackling. Crackling is your chicken droppings and the excess flour that’s fallen down to the base through the filter into something known as the collector.
Each week or so, they simply filter out that collector and keep the crackling and append it into a container that’s then kept in a fridge for about seven days until it can be utilized.
Then, once these days are up, they make use of that crackling for making the gravy. So the gravy has water, powder, and crackling.
So, to answer the question, I guess, if speaking technically, the gravy can be contemplated vegetarian because all it’s really is the extra flour that has fallen off of your chicken and is then fried. But it is not really vegetarian because you are actually cooking the chicken in vegetable oil.