Were they ravens or crows? I would believe crows because ravens don't usually flock unless there is a very large amount of food (they're scavengers). Ravens are very big and have hooked bills. They're wingspan is about 3-4ft.
From your description, I would guess they are crows, and they normally are omens of death. So if you believe in omens and feel strongly that this is an omen, prepare yourself for the news of the death of a loved one and keep a watch on others and make sure they take proper precautions. Becareful yourself as well, and don't do anything risky. Signs are only warnings, not guaranties.
Ravens and wolves get along. So if they WERE in fact ravens, they may have thought the dogs knew where food was.