I have a 9 yr old lab/chow mix that has stopped eating. I recently changed her diet from pedigree lamb and rice to beneful. It is also very hot outside and she does not handle heat very well. She has been to the vet and he cannot find anything wrong. She will not eat anything at all but drinks large amounts of water. Any help will be appreciated I have tried different types of dog food and people food such as hot dogs bacon and steak. I went and got her old dog food and she will not eat that either ANY SUGGESTIONS PLEASE HELP. THANK YOU