It would be highly unusual for swan parents to accept another cygnet from a different family. Usually, the adult swans chase other swans from their immediate nesting area. This chasing may result in serious injury and even death to the cygnets which is why the introduction of cygnets from another family is not recommended. However, based upon individual attributes, there can always be an exception to this rule.

Some birds such as geese, various species of ducks and even songbirds will accept the young of other birds to raise as their own. The Regal Swan
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