I have a German Shepherd/Chow mix named Ruby approximately 6-7 months old and she is scaring me because she is not acting herself. Monday morning I fed her the usual puppy chow and she gobbled it up, however when I fed her that evening she only ate about a quarter of it. Tuesday morning she didn't eat anything but she was still jumping around and playing like her usual self. Tuesday evening when I called her she wouldn't come and when she finally came she was sad and not playful at all and she won't eat anything. I am worried about her. It was about 100 degrees today and she's an outside dog but she had ample water and plenty of shade to get in out of the heat. What could be wrong? Any suggestions?