No they cannot.
Anything involving chocolate is usually toxic to a majority of animals, whether pudding or not. If it's not part of their natural diet then I'd say that it's highly unlikely that they can, and it will likely make them ill. Giving an owl chocolate pudding is not the best idea.
Is that something they would find in the wild? Probably not, and most animals do not tolerate chocolate well, so I would advise against it.
No . Chocolate is poison to birds.
