Did your dog eat a cork?
If he did eat it was it chewed or swallowed whole?
What type of dog are we discussing?
Cork itself is not toxic, but if swallowed whole it can cause a blockage in the intestinal tract. If chewed, it should pass. I would normally suggest inducing vomiting if an hour or less, but if swallowed whole it can lodge in the wind pipe, so I am hesitatnt to advise that. At this point, The choice would be to wait and see if it passes in the stool. You could take the dogs in and have them X rayed and see if the Vet can retrieve it with an endoscope if swallowed whole or take a wait and see stand. Watch for symptoms of a problem which can include vomiting, diarrhea, tender abomen, diarrhea, constipation or a combination of the issues listed. The thing you have in your favor is the both dogs are large breed and have a better chance to pass the cork if it was swallowed whole. Joan