The brand I feed has the same analysis, but is half the price. Why is that?

The analysis is by no means a guarantee of a quality food. Adequate and sometimes impressive levels of protein and fat can be be listed in a cheaper food but your pet may still lack energy, a glossy coat and not have that gleam of health that you would expect. The reason for this the quality of ingredients and how easily your pets digestive system can access and use the nutrients in the food. Soya meal - a cheap vegetable protein substitute - can produce a high enough protein level, however, as dogs and cats are first and foremost carnivores - designed to eat meat by millions of years of evolution - vegetable proteins are quite difficult for their metabolism to break down and make use of its component parts - the end result - your pet really isn't receiving the protein levels he needs. Vegetable fats do provide an instant energy kick to some degree and allow fat soluble vitamins to be digested. But again, as dogs and cats are carnivores their bodies are designed to utilise animal products far more efficiently - the most easily digested and therefore economically used in your pets digestive system are animal fats, with chicken fat having the highest digestibility. A cheaper food may seem to provide all the nutrients that your pet requires, but if the ingredients are poor quality or a substitute for good meat products then much of what goes in the front end cannot be used by the body and comes out the back as waste!