Adopted dog, not eating much, and barfed yellow bile?

Usually, yellow bile indicates the dog's stomach was expecting food (like if it is always fed at a certain time), and didn't get it. The stomach produces acid, and when there is no food to process, it is vomited up. Since the dog isn't eating much, this isn't out of the ordinary. As the dog settles in, and starts eating more, this should go away. It's a good idea to vary feeding times though, so this doesn't happen if dinner is late for some reason. My dog is fed anywhere from 7:30 pm to 10:30 pm to prevent the stomach from "anticipating" dinner, and having this kind of reaction.