Tagged sheep nailed to another flock

Solve the problem, arguing your answer with links to sources of law.
A labeled sheep nailed to another flock and grazed in a strange meadow all summer. In the end, she was found by the owner. Is he entitled to take her away, despite the protests of the owner of the herd and meadow? Does the fact that sheep ownership was open and violent matter? Could the claim for damages related to feeding and guarding a sheep be taken into account?

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